diff --git a/Makefile b/Makefile
index 9403b83e..5bf77ee1 100644
--- a/Makefile
+++ b/Makefile
@@ -35,7 +35,7 @@ OBJS = swad_account.o swad_action.o swad_agenda.o swad_alert.o \
        swad_course_config.o swad_cryptography.o \
        swad_database.o swad_date.o swad_degree.o swad_degree_config.o \
        swad_degree_type.o swad_department.o swad_duplicate.o \
-       swad_enrolment.o swad_exam.o swad_exam_log.o \
+       swad_enrolment.o swad_error.o swad_exam.o swad_exam_log.o \
        swad_exam_print.o swad_exam_result.o swad_exam_session.o \
        swad_exam_set.o \
        swad_figure.o swad_figure_cache.o swad_file.o swad_file_browser.o \
diff --git a/icon/filext32x32/cct32x32.gif b/icon/filext32x32/cct32x32.gif
new file mode 100644
index 00000000..5bf90d0c
Binary files /dev/null and b/icon/filext32x32/cct32x32.gif differ
diff --git a/icon/filext32x32/clf32x32.gif b/icon/filext32x32/clf32x32.gif
new file mode 100644
index 00000000..5bf90d0c
Binary files /dev/null and b/icon/filext32x32/clf32x32.gif differ
diff --git a/icon/filext32x32/tim32x32.gif b/icon/filext32x32/tim32x32.gif
new file mode 100644
index 00000000..5bf90d0c
Binary files /dev/null and b/icon/filext32x32/tim32x32.gif differ
diff --git a/swad_API.c b/swad_API.c
index 0217a89e..bf8e8e66 100644
--- a/swad_API.c
+++ b/swad_API.c
@@ -105,6 +105,7 @@ cp -f /home/acanas/swad/swad/swad /var/www/cgi-bin/
 #include "swad_API.h"
 #include "swad_attendance.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_file_browser.h"
 #include "swad_forum.h"
 #include "swad_global.h"
@@ -1653,7 +1654,7 @@ static int API_WritePageIntoHTMLBuffer (struct soap *soap,
       /***** Write page from file to text buffer *****/
       /* Open file */
       if ((FileHTML = fopen (PathRelFileHTML,"rb")) == NULL)
-	 Lay_ShowErrorAndExit ("Can not open XML file.");
+	 Err_ShowErrorAndExit ("Can not open XML file.");
 
       /* Compute file size */
       fseek (FileHTML,0L,SEEK_END);
@@ -1664,7 +1665,7 @@ static int API_WritePageIntoHTMLBuffer (struct soap *soap,
       if ((*HTMLBuffer = malloc (Length + 1)) == NULL)
 	{
 	 fclose (FileHTML);
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
          return soap_receiver_fault (soap,
                                      "Web page can not be copied into buffer",
                                      "Not enough memory for buffer");
@@ -2262,7 +2263,7 @@ int swad__sendMyGroups (struct soap *soap,
          /***** Create a list of groups selected from myGroups *****/
          if ((LstGrpsIWant.GrpCods = calloc (LstGrpsIWant.NumGrps,
                                              sizeof (*LstGrpsIWant.GrpCods))) == NULL)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
          for (NumGrp = 0, Ptr = myGroups;
               *Ptr;
               NumGrp++)
@@ -2836,7 +2837,7 @@ static void API_GetLstGrpsSel (const char *Groups)
       // Here NestedCalls is always 1
       if ((Gbl.Crs.Grps.LstGrpsSel.GrpCods = calloc (Gbl.Crs.Grps.LstGrpsSel.NumGrps,
                                                      sizeof (*Gbl.Crs.Grps.LstGrpsSel.GrpCods))) == NULL)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
 
       for (Ptr = Groups, NumGrp = 0;
 	   *Ptr;
@@ -3636,7 +3637,7 @@ int swad__sendMessage (struct soap *soap,
 
    /***** Allocate space for query *****/
    if ((Query = malloc (API_MAX_BYTES_QUERY_RECIPIENTS + 1)) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Build query for recipients from database *****/
    if (ReplyUsrCod > 0)
diff --git a/swad_HTML.c b/swad_HTML.c
index 6948a57a..83712a21 100644
--- a/swad_HTML.c
+++ b/swad_HTML.c
@@ -30,6 +30,7 @@
 #include <stdio.h>		// For vasprintf
 #include <stdlib.h>		// For free
 
+#include "swad_error.h"
 #include "swad_global.h"
 #include "swad_HTML.h"
 
@@ -128,7 +129,7 @@ void HTM_TABLE_Begin (const char *fmt,...)
 	 NumBytesPrinted = vasprintf (&Class,fmt,ap);
 	 va_end (ap);
 	 if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Print HTML *****/
 	 HTM_TxtF ("<table class=\"%s\">",Class);
@@ -252,7 +253,7 @@ void HTM_TBODY_Begin (const char *fmt,...)
 	 NumBytesPrinted = vasprintf (&Attr,fmt,ap);
 	 va_end (ap);
 	 if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Print HTML *****/
 	 HTM_TxtF ("<tbody %s>",Attr);
@@ -294,7 +295,7 @@ void HTM_TR_Begin (const char *fmt,...)
 	 NumBytesPrinted = vasprintf (&Attr,fmt,ap);
 	 va_end (ap);
 	 if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Print HTML *****/
 	 HTM_TxtF ("<tr %s>",Attr);
@@ -391,7 +392,7 @@ static void HTM_TH_BeginAttr (const char *fmt,...)
 	 NumBytesPrinted = vasprintf (&Attr,fmt,ap);
 	 va_end (ap);
 	 if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Print HTML *****/
 	 HTM_TxtF ("<th %s>",Attr);
@@ -453,7 +454,7 @@ void HTM_TD_Begin (const char *fmt,...)
 	 NumBytesPrinted = vasprintf (&Attr,fmt,ap);
 	 va_end (ap);
 	 if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Print HTML *****/
 	 HTM_TxtF ("<td %s>",Attr);
@@ -528,7 +529,7 @@ void HTM_DIV_Begin (const char *fmt,...)
 	 NumBytesPrinted = vasprintf (&Attr,fmt,ap);
 	 va_end (ap);
 	 if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Print HTML *****/
 	 HTM_TxtF ("<div %s>",Attr);
@@ -619,7 +620,7 @@ void HTM_SPAN_Begin (const char *fmt,...)
 	 NumBytesPrinted = vasprintf (&Attr,fmt,ap);
 	 va_end (ap);
 	 if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Print HTML *****/
 	 HTM_TxtF ("<span %s>",Attr);
@@ -685,7 +686,7 @@ void HTM_UL_Begin (const char *fmt,...)
 	 NumBytesPrinted = vasprintf (&Attr,fmt,ap);
 	 va_end (ap);
 	 if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Print HTML *****/
 	 HTM_TxtF ("<ul %s>",Attr);
@@ -734,7 +735,7 @@ void HTM_LI_Begin (const char *fmt,...)
 	 NumBytesPrinted = vasprintf (&Attr,fmt,ap);
 	 va_end (ap);
 	 if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Print HTML *****/
 	 HTM_TxtF ("<li %s>",Attr);
@@ -838,7 +839,7 @@ void HTM_A_Begin (const char *fmt,...)
 	 NumBytesPrinted = vasprintf (&Attr,fmt,ap);
 	 va_end (ap);
 	 if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Print HTML *****/
 	 HTM_TxtF ("<a %s>",Attr);
@@ -915,7 +916,7 @@ void HTM_PARAM (const char *Name,
 	 NumBytesPrinted = vasprintf (&Value,fmt,ap);
 	 va_end (ap);
 	 if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Print HTML *****/
 	 HTM_TxtF ("\n<param name=\"%s\" value=\"%s\">",Name,Value);
@@ -942,7 +943,7 @@ void HTM_LABEL_Begin (const char *fmt,...)
 	 NumBytesPrinted = vasprintf (&Attr,fmt,ap);
 	 va_end (ap);
 	 if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Print HTML *****/
 	 HTM_TxtF ("<label %s>",Attr);
@@ -996,7 +997,7 @@ void HTM_INPUT_TEXT (const char *Name,unsigned MaxLength,const char *Value,
 	 NumBytesPrinted = vasprintf (&Attr,fmt,ap);
 	 va_end (ap);
 	 if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Print attributes *****/
 	 HTM_SPTxt (Attr);
@@ -1030,7 +1031,7 @@ void HTM_INPUT_SEARCH (const char *Name,unsigned MaxLength,const char *Value,
 	 NumBytesPrinted = vasprintf (&Attr,fmt,ap);
 	 va_end (ap);
 	 if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Print attributes *****/
 	 HTM_SPTxt (Attr);
@@ -1061,7 +1062,7 @@ void HTM_INPUT_TEL (const char *Name,const char *Value,
 	 NumBytesPrinted = vasprintf (&Attr,fmt,ap);
 	 va_end (ap);
 	 if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Print attributes *****/
 	 HTM_SPTxt (Attr);
@@ -1095,7 +1096,7 @@ void HTM_INPUT_EMAIL (const char *Name,unsigned MaxLength,const char *Value,
 	 NumBytesPrinted = vasprintf (&Attr,fmt,ap);
 	 va_end (ap);
 	 if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Print attributes *****/
 	 HTM_SPTxt (Attr);
@@ -1126,7 +1127,7 @@ void HTM_INPUT_URL (const char *Name,const char *Value,
 	 NumBytesPrinted = vasprintf (&Attr,fmt,ap);
 	 va_end (ap);
 	 if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Print attributes *****/
 	 HTM_SPTxt (Attr);
@@ -1161,7 +1162,7 @@ void HTM_INPUT_FILE (const char *Name,const char *Accept,
 	 NumBytesPrinted = vasprintf (&Attr,fmt,ap);
 	 va_end (ap);
 	 if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Print attributes *****/
 	 HTM_SPTxt (Attr);
@@ -1221,7 +1222,7 @@ void HTM_INPUT_PASSWORD (const char *Name,const char *PlaceHolder,
 	 NumBytesPrinted = vasprintf (&Attr,fmt,ap);
 	 va_end (ap);
 	 if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Print attributes *****/
 	 HTM_SPTxt (Attr);
@@ -1254,7 +1255,7 @@ void HTM_INPUT_LONG (const char *Name,long Min,long Max,long Value,
 	 NumBytesPrinted = vasprintf (&Attr,fmt,ap);
 	 va_end (ap);
 	 if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Print attributes *****/
 	 HTM_SPTxt (Attr);
@@ -1301,7 +1302,7 @@ void HTM_INPUT_FLOAT (const char *Name,double Min,double Max,
 	 NumBytesPrinted = vasprintf (&Attr,fmt,ap);
 	 va_end (ap);
 	 if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Print attributes *****/
 	 HTM_SPTxt (Attr);
@@ -1330,7 +1331,7 @@ void HTM_INPUT_RADIO (const char *Name,bool SubmitOnClick,
 	 NumBytesPrinted = vasprintf (&Attr,fmt,ap);
 	 va_end (ap);
 	 if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Print attributes *****/
 	 HTM_SPTxt (Attr);
@@ -1362,7 +1363,7 @@ void HTM_INPUT_CHECKBOX (const char *Name,HTM_SubmitOnChange_t SubmitOnChange,
 	 NumBytesPrinted = vasprintf (&Attr,fmt,ap);
 	 va_end (ap);
 	 if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Print attributes *****/
 	 HTM_SPTxt (Attr);
@@ -1476,7 +1477,7 @@ void HTM_TEXTAREA_Begin (const char *fmt,...)
 	 NumBytesPrinted = vasprintf (&Attr,fmt,ap);
 	 va_end (ap);
 	 if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Print HTML *****/
 	 HTM_TxtF ("<textarea %s>",Attr);
@@ -1526,7 +1527,7 @@ void HTM_SELECT_Begin (HTM_SubmitOnChange_t SubmitOnChange,
 	 NumBytesPrinted = vasprintf (&Attr,fmt,ap);
 	 va_end (ap);
 	 if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Print HTML *****/
 	 HTM_TxtF ("<select %s",Attr);
@@ -1614,7 +1615,7 @@ void HTM_OPTION (HTM_Type_t Type,const void *ValuePtr,bool Selected,bool Disable
 	 NumBytesPrinted = vasprintf (&Content,fmt,ap);
 	 va_end (ap);
 	 if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Print HTML *****/
 	 HTM_Txt (Content);
@@ -1661,7 +1662,7 @@ void HTM_IMG (const char *URL,const char *Icon,const char *Title,
 	 NumBytesPrinted = vasprintf (&Attr,fmt,ap);
 	 va_end (ap);
 	 if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Print attributes *****/
 	 HTM_SPTxt (Attr);
@@ -1762,7 +1763,7 @@ void HTM_TxtF (const char *fmt,...)
 	 NumBytesPrinted = vasprintf (&Attr,fmt,ap);
 	 va_end (ap);
 	 if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Print HTML *****/
 	 HTM_Txt (Attr);
diff --git a/swad_ID.c b/swad_ID.c
index 6020f091..a5a1b082 100644
--- a/swad_ID.c
+++ b/swad_ID.c
@@ -33,6 +33,7 @@
 #include "swad_account.h"
 #include "swad_box.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_HTML.h"
@@ -151,7 +152,7 @@ void ID_ReallocateListIDs (struct UsrData *UsrDat,unsigned NumIDs)
 
    /***** Allocate space for the list *****/
    if ((UsrDat->IDs.List = malloc (NumIDs * sizeof (*UsrDat->IDs.List))) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
   }
 
 /*****************************************************************************/
@@ -197,7 +198,7 @@ unsigned ID_GetListUsrCodsFromUsrID (struct UsrData *UsrDat,
       /***** Allocate memory for subquery string *****/
       MaxLength = 512 + UsrDat->IDs.Num * (1 + ID_MAX_BYTES_USR_ID + 1) - 1;
       if ((SubQueryAllUsrs = malloc (MaxLength + 1)) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
       SubQueryAllUsrs[0] = '\0';
 
       /***** Get user's code(s) from database *****/
diff --git a/swad_MFU.c b/swad_MFU.c
index aba6ed82..9317ecea 100644
--- a/swad_MFU.c
+++ b/swad_MFU.c
@@ -33,6 +33,7 @@
 #include "swad_box.h"
 #include "swad_config.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_HTML.h"
@@ -80,7 +81,7 @@ void MFU_AllocateMFUActions (struct MFU_ListMFUActions *ListMFUActions,unsigned
   {
    if ((ListMFUActions->Actions = malloc (MaxActionsShown *
                                           sizeof (*ListMFUActions->Actions))) == NULL)
-      Lay_ShowErrorAndExit ("Can not allocate memory for list of most frequently used actions.");
+      Err_ShowErrorAndExit ("Can not allocate memory for list of most frequently used actions.");
   }
 
 /*****************************************************************************/
@@ -357,7 +358,7 @@ void MFU_UpdateMFUActions (void)
      {
       row = mysql_fetch_row (mysql_res);
       if (sscanf (row[0],"%lf",&Score) != 1)
-         Lay_ShowErrorAndExit ("Error when getting score for current action.");
+         Err_ShowErrorAndExit ("Error when getting score for current action.");
       Score *= MFU_INCREASE_FACTOR;
       if (Score > MFU_MAX_SCORE)
          Score = MFU_MAX_SCORE;
diff --git a/swad_QR.c b/swad_QR.c
index e7cb898c..4f82556d 100644
--- a/swad_QR.c
+++ b/swad_QR.c
@@ -30,6 +30,7 @@
 #include <stdlib.h>		// For free
 
 #include "swad_action.h"
+#include "swad_error.h"
 #include "swad_global.h"
 #include "swad_HTML.h"
 #include "swad_ID.h"
@@ -118,7 +119,7 @@ void QR_ImageQRCode (const char *QRString)
 
    if (asprintf (&URL,"https://chart.googleapis.com/chart?cht=qr&amp;chs=%ux%u&amp;chl=%s",
 		 QR_CODE_SIZE,QR_CODE_SIZE,QRString) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    HTM_IMG (URL,NULL,QRString,
 	    "style=\"width:%upx;height:%upx;border:1px dashed silver;\"",
 	    QR_CODE_SIZE,QR_CODE_SIZE);
@@ -141,13 +142,13 @@ void QR_LinkTo (unsigned Size,const char *ParamName,long Cod)
      {
       if (asprintf (&URL,"https://chart.googleapis.com/chart?cht=qr&amp;chs=%ux%u&amp;chl=%s/?%s=%ld",
 		    Size,Size,Cfg_URL_SWAD_CGI,ParamName,Cod) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
      }
    else
      {
       if (asprintf (&URL,"https://chart.googleapis.com/chart?cht=qr&amp;chs=%ux%u&amp;chl=%s/",
 		    Size,Size,Cfg_URL_SWAD_CGI) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
      }
    HTM_IMG (URL,NULL,Txt_Shortcut,
 	    "style=\"width:%upx;height:%upx;\"",Size,Size);
@@ -170,7 +171,7 @@ void QR_ExamAnnnouncement (void)
 		 300,300,
                  Cfg_URL_SWAD_CGI,Gbl.Hierarchy.Crs.CrsCod,
 		 Act_GetActCod (ActSeeAllExaAnn)) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    HTM_IMG (URL,NULL,Txt_Link_to_call_for_exam,
 	    "style=\"width:250px;height:250px;\"");
    free (URL);
diff --git a/swad_RSS.c b/swad_RSS.c
index 8d02812e..a1eb53b3 100644
--- a/swad_RSS.c
+++ b/swad_RSS.c
@@ -32,6 +32,7 @@
 #include "swad_call_for_exam.h"
 #include "swad_changelog.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_global.h"
 #include "swad_notice.h"
 #include "swad_RSS.h"
@@ -74,7 +75,7 @@ void RSS_UpdateRSSFileForACrs (struct Crs_Course *Crs)
    snprintf (PathRelPublRSSFile,sizeof (PathRelPublRSSFile),"%s/%s",
 	     PathRelPublRSSDir,Cfg_RSS_FILE);
    if ((FileRSS = fopen (PathRelPublRSSFile,"wb")) == NULL)
-      Lay_ShowErrorAndExit ("Can not create RSS file.");
+      Err_ShowErrorAndExit ("Can not create RSS file.");
 
    /***** Write RSS header *****/
    fprintf (FileRSS,"<?xml version=\"1.0\" encoding=\"windows-1252\"?>\n");
@@ -186,7 +187,7 @@ static void RSS_WriteNotices (FILE *FileRSS,struct Crs_Course *Crs)
 
          /* Get notice code */
          if (sscanf (row[0],"%ld",&NotCod) != 1)
-            Lay_WrongNoticeExit ();
+            Err_WrongNoticeExit ();
 
          /* Get UTC date-time of publication */
          CreatTimeUTC = 0L;
@@ -290,7 +291,7 @@ static void RSS_WriteCallsForExams (FILE *FileRSS,struct Crs_Course *Crs)
 
 	    /* Get call for exam code */
 	    if (sscanf (row[0],"%ld",&ExaCod) != 1)
-	       Lay_WrongCallForExamExit ();
+	       Err_WrongCallForExamExit ();
 
 	    /* Get UTC date-time of publication */
 	    CallTimeUTC = 0L;
diff --git a/swad_account.c b/swad_account.c
index d5ff22b7..3aa11a8e 100644
--- a/swad_account.c
+++ b/swad_account.c
@@ -36,6 +36,7 @@
 #include "swad_database.h"
 #include "swad_duplicate.h"
 #include "swad_enrolment.h"
+#include "swad_error.h"
 #include "swad_exam_print.h"
 #include "swad_follow.h"
 #include "swad_form.h"
@@ -738,7 +739,7 @@ void Acc_CreateNewUsr (struct UsrData *UsrDat,bool CreatingMyOwnAccount)
 
    /***** Trivial check: user's code should be <= 0 *****/
    if (UsrDat->UsrCod > 0)
-      Lay_ShowErrorAndExit ("Can not create new user.");
+      Err_ShowErrorAndExit ("Can not create new user.");
 
    /***** Create encrypted user's code *****/
    Acc_CreateNewEncryptedUsrCod (UsrDat);
@@ -844,7 +845,7 @@ static void Acc_CreateNewEncryptedUsrCod (struct UsrData *UsrDat)
           break;
      }
    if (NumTry == MAX_TRY)
-      Lay_ShowErrorAndExit ("Can not create a new encrypted user's code.");
+      Err_ShowErrorAndExit ("Can not create a new encrypted user's code.");
    }
 
 /*****************************************************************************/
diff --git a/swad_agenda.c b/swad_agenda.c
index 7a1dbc74..2c1f6f5d 100644
--- a/swad_agenda.c
+++ b/swad_agenda.c
@@ -36,6 +36,7 @@
 #include "swad_box.h"
 #include "swad_database.h"
 #include "swad_date.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_group.h"
@@ -821,7 +822,7 @@ static void Agd_ShowOneEvent (struct Agd_Agenda *Agenda,
 	StartEndTime++)
      {
       if (asprintf (&Id,"agd_date_%u_%u",(unsigned) StartEndTime,UniqueId) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       HTM_TD_Begin ("id=\"%s\" class=\"%s LB COLOR%u\"",
 		    Id,
 		    AgdEvent.Hidden ? Dat_TimeStatusClassHidden[AgdEvent.TimeStatus] :
@@ -1074,7 +1075,7 @@ static void Agd_GetListEvents (struct Agd_Agenda *Agenda,
 	   {
 	    if (asprintf (&UsrSubQuery,"UsrCod=%ld",
 			  Gbl.Usrs.Me.UsrDat.UsrCod) < 0)
-	       Lay_NotEnoughMemoryExit ();
+	       Err_NotEnoughMemoryExit ();
 	    if (AgendaType == Agd_MY_AGENDA_TODAY)
 	       Str_Copy (Past__FutureEventsSubQuery,
 			 " AND DATE(StartTime)<=CURDATE()"
@@ -1131,7 +1132,7 @@ static void Agd_GetListEvents (struct Agd_Agenda *Agenda,
       case Agd_ANOTHER_AGENDA:
 	 if (asprintf (&UsrSubQuery,"UsrCod=%ld",
 	               Gbl.Usrs.Other.UsrDat.UsrCod) < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 	 if (AgendaType == Agd_ANOTHER_AGENDA_TODAY)
 	    Str_Copy (Past__FutureEventsSubQuery,
 		      " AND DATE(StartTime)<=CURDATE()"
@@ -1170,7 +1171,7 @@ static void Agd_GetListEvents (struct Agd_Agenda *Agenda,
 	 /***** Create list of events *****/
 	 if ((Agenda->LstAgdCods = calloc ((size_t) Agenda->Num,
 	                                   sizeof (*Agenda->LstAgdCods))) == NULL)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Get the events codes *****/
 	 for (NumEvent = 0;
@@ -1178,7 +1179,7 @@ static void Agd_GetListEvents (struct Agd_Agenda *Agenda,
 	      NumEvent++)
 	    /* Get next event code */
 	    if ((Agenda->LstAgdCods[NumEvent] = DB_GetNextCode (mysql_res)) < 0)
-	       Lay_WrongEventExit ();
+	       Err_WrongEventExit ();
 	}
 
       /***** Free structure that stores the query result *****/
@@ -1327,7 +1328,7 @@ void Agd_AskRemEvent (void)
 
    /***** Get event code *****/
    if ((AgdEvent.AgdCod = Agd_GetParamAgdCod ()) < 0)
-      Lay_WrongEventExit ();
+      Err_WrongEventExit ();
 
    /***** Get data of the event from database *****/
    AgdEvent.UsrCod = Gbl.Usrs.Me.UsrDat.UsrCod;
@@ -1363,7 +1364,7 @@ void Agd_RemoveEvent (void)
 
    /***** Get event code *****/
    if ((AgdEvent.AgdCod = Agd_GetParamAgdCod ()) < 0)
-      Lay_WrongEventExit ();
+      Err_WrongEventExit ();
 
    /***** Get data of the event from database *****/
    AgdEvent.UsrCod = Gbl.Usrs.Me.UsrDat.UsrCod;
@@ -1402,7 +1403,7 @@ void Agd_HideEvent (void)
 
    /***** Get event code *****/
    if ((AgdEvent.AgdCod = Agd_GetParamAgdCod ()) < 0)
-      Lay_WrongEventExit ();
+      Err_WrongEventExit ();
 
    /***** Get data of the event from database *****/
    AgdEvent.UsrCod = Gbl.Usrs.Me.UsrDat.UsrCod;
@@ -1438,7 +1439,7 @@ void Agd_UnhideEvent (void)
 
    /***** Get event code *****/
    if ((AgdEvent.AgdCod = Agd_GetParamAgdCod ()) < 0)
-      Lay_WrongEventExit ();
+      Err_WrongEventExit ();
 
    /***** Get data of the event from database *****/
    AgdEvent.UsrCod = Gbl.Usrs.Me.UsrDat.UsrCod;
@@ -1475,7 +1476,7 @@ void Agd_MakeEventPrivate (void)
 
    /***** Get event code *****/
    if ((AgdEvent.AgdCod = Agd_GetParamAgdCod ()) < 0)
-      Lay_WrongEventExit ();
+      Err_WrongEventExit ();
 
    /***** Get data of the event from database *****/
    AgdEvent.UsrCod = Gbl.Usrs.Me.UsrDat.UsrCod;
@@ -1516,7 +1517,7 @@ void Agd_MakeEventPublic (void)
 
    /***** Get event code *****/
    if ((AgdEvent.AgdCod = Agd_GetParamAgdCod ()) < 0)
-      Lay_WrongEventExit ();
+      Err_WrongEventExit ();
 
    /***** Get data of the event from database *****/
    AgdEvent.UsrCod = Gbl.Usrs.Me.UsrDat.UsrCod;
@@ -1932,7 +1933,7 @@ unsigned Agd_GetNumUsrsWithEvents (Hie_Lvl_Level_t Scope)
 			  " AND crs_users.UsrCod=agd_agendas.UsrCod",
                         Gbl.Hierarchy.Crs.CrsCod);
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 return 0;	// Not reached
      }
   }
@@ -2023,7 +2024,7 @@ unsigned Agd_GetNumEvents (Hie_Lvl_Level_t Scope)
 			  " AND crs_users.UsrCod=agd_agendas.UsrCod",
                         Gbl.Hierarchy.Crs.CrsCod);
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 return 0;	// Not reached
      }
   }
diff --git a/swad_alert.c b/swad_alert.c
index d082b242..8a36ad17 100644
--- a/swad_alert.c
+++ b/swad_alert.c
@@ -33,6 +33,7 @@
 #include <string.h>		// For string functions
 
 #include "swad_alert.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_HTML.h"
@@ -78,7 +79,7 @@ void Ale_CreateAlert (Ale_AlertType_t Type,const char *Section,
    size_t i;
 
    if (Gbl.Alerts.Num + 1 > Ale_MAX_ALERTS)
-      Lay_ShowErrorAndExit ("Too many alerts.");
+      Err_ShowErrorAndExit ("Too many alerts.");
 
    i = Gbl.Alerts.Num;
    Gbl.Alerts.Num++;
@@ -90,13 +91,13 @@ void Ale_CreateAlert (Ale_AlertType_t Type,const char *Section,
       if (Section[0])
 	 if (asprintf (&Gbl.Alerts.List[i].Section,"%s",
 	               Section) < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
    va_start (ap,fmt);
    NumBytesPrinted = vasprintf (&Gbl.Alerts.List[i].Text,fmt,ap);
    va_end (ap);
    if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
   }
 
 /*****************************************************************************/
@@ -203,7 +204,7 @@ static void Ale_ResetAlert (size_t i)
 void Ale_ShowAlertsAndExit ()
   {
    Ale_ShowAlerts (NULL);
-   Lay_ShowErrorAndExit (NULL);
+   Err_ShowErrorAndExit (NULL);
   }
 
 /*****************************************************************************/
@@ -254,7 +255,7 @@ void Ale_ShowAlert (Ale_AlertType_t AlertType,const char *fmt,...)
       NumBytesPrinted = vasprintf (&Txt,fmt,ap);
       va_end (ap);
       if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
 
       /***** Show alert *****/
       Ale_ShowFixAlert (AlertType,Txt);
@@ -328,7 +329,7 @@ void Ale_ShowAlertAndButton (Act_Action_t NextAction,const char *Anchor,const ch
    NumBytesPrinted = vasprintf (&Txt,fmt,ap);
    va_end (ap);
    if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /****** Print fix alert and button ******/
    Ale_ShowFixAlertAndButton1 (AlertType,Txt);
@@ -355,7 +356,7 @@ void Ale_ShowAlertAndButton1 (Ale_AlertType_t AlertType,const char *fmt,...)
    NumBytesPrinted = vasprintf (&Txt,fmt,ap);
    va_end (ap);
    if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /****** Print start of fix alert and button ******/
    Ale_ShowFixAlertAndButton1 (AlertType,Txt);
diff --git a/swad_announcement.c b/swad_announcement.c
index 981303a2..d8bea8a0 100644
--- a/swad_announcement.c
+++ b/swad_announcement.c
@@ -28,6 +28,7 @@
 #include "swad_announcement.h"
 #include "swad_box.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_HTML.h"
@@ -155,7 +156,7 @@ void Ann_ShowAllAnnouncements (void)
 
       /* Get announcement code (row[0]) */
       if (sscanf (row[0],"%ld",&AnnCod) != 1)
-	 Lay_WrongAnnouncementExit ();
+	 Err_WrongAnnouncementExit ();
 
       /* Get status of the announcement (row[1]) */
       Status = Ann_OBSOLETE_ANNOUNCEMENT;
@@ -165,7 +166,7 @@ void Ann_ShowAllAnnouncements (void)
 
       /* Get roles (row[2]) */
       if (sscanf (row[2],"%u",&Roles) != 1)
-      	 Lay_ShowErrorAndExit ("Error when reading roles of announcement.");
+      	 Err_ShowErrorAndExit ("Error when reading roles of announcement.");
 
       /* Get the subject (row[3]), the content (row[4]), and insert links */
       Str_Copy (Subject,row[3],sizeof (Subject) - 1);
@@ -260,7 +261,7 @@ void Ann_ShowMyAnnouncementsNotMarkedAsSeen (void)
 
 	 /* Get announcement code (row[0]) */
 	 if (sscanf (row[0],"%ld",&AnnCod) != 1)
-	    Lay_WrongAnnouncementExit ();
+	    Err_WrongAnnouncementExit ();
 
 	 /* Get the subject (row[1]), the content (row[2]), and insert links */
 	 Str_Copy (Subject,row[1],sizeof (Subject) - 1);
@@ -395,7 +396,7 @@ static long Ann_GetParamAnnCod (void)
 
    /***** Get announcement code *****/
    if ((AnnCod = Par_GetParToLong ("AnnCod")) <= 0)
-      Lay_WrongAnnouncementExit ();
+      Err_WrongAnnouncementExit ();
 
    return AnnCod;
   }
diff --git a/swad_assignment.c b/swad_assignment.c
index d56d9a8b..5c153ec7 100644
--- a/swad_assignment.c
+++ b/swad_assignment.c
@@ -35,6 +35,7 @@
 #include "swad_assignment.h"
 #include "swad_box.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_figure.h"
 #include "swad_form.h"
 #include "swad_global.h"
@@ -416,7 +417,7 @@ static void Asg_ShowOneAssignment (struct Asg_Assignments *Assignments,
 	StartEndTime++)
      {
       if (asprintf (&Id,"asg_date_%u_%u",(unsigned) StartEndTime,UniqueId) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       if (PrintView)
 	 HTM_TD_Begin ("id=\"%s\" class=\"%s LB\"",
 		       Id,
@@ -549,7 +550,7 @@ static void Asg_WriteAssignmentFolder (struct Asg_Assignment *Asg,bool PrintView
 	    Frm_BeginForm (ActFrmCreAsgCrs);
 	    break;
 	 default:
-            Lay_WrongRoleExit ();
+            Err_WrongRoleExit ();
 	    break;
         }
       Str_Copy (Gbl.FileBrowser.FilFolLnk.Path,Brw_INTERNAL_NAME_ROOT_FOLDER_ASSIGNMENTS,
@@ -734,7 +735,7 @@ static void Asg_GetListAssignments (struct Asg_Assignments *Assignments)
       /***** Create list of assignments *****/
       if ((Assignments->LstAsgCods = calloc (NumAsgs,
                                              sizeof (*Assignments->LstAsgCods))) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
 
       /***** Get the assignments codes *****/
       for (NumAsg = 0;
@@ -743,7 +744,7 @@ static void Asg_GetListAssignments (struct Asg_Assignments *Assignments)
         {
          /* Get next assignment code */
          if ((Assignments->LstAsgCods[NumAsg] = DB_GetNextCode (mysql_res)) <= 0)
-            Lay_WrongAssignmentExit ();
+            Err_WrongAssignmentExit ();
         }
      }
    else
@@ -985,7 +986,7 @@ void Asg_GetNotifAssignment (char SummaryStr[Ntf_MAX_BYTES_SUMMARY + 1],
 	{
 	 Length = strlen (row[1]);
 	 if ((*ContentStr = malloc (Length + 1)) == NULL)
-            Lay_NotEnoughMemoryExit ();
+            Err_NotEnoughMemoryExit ();
 	 Str_Copy (*ContentStr,row[1],Length);
 	}
      }
@@ -1034,7 +1035,7 @@ void Asg_ReqRemAssignment (void)
 
    /***** Get assignment code *****/
    if ((Asg.AsgCod = Asg_GetParamAsgCod ()) <= 0)
-      Lay_WrongAssignmentExit ();
+      Err_WrongAssignmentExit ();
 
    /***** Get data of the assignment from database *****/
    Asg_GetDataOfAssignmentByCod (&Asg);
@@ -1071,7 +1072,7 @@ void Asg_RemoveAssignment (void)
 
    /***** Get assignment code *****/
    if ((Asg.AsgCod = Asg_GetParamAsgCod ()) <= 0)
-      Lay_WrongAssignmentExit ();
+      Err_WrongAssignmentExit ();
 
    /***** Get data of the assignment from database *****/
    Asg_GetDataOfAssignmentByCod (&Asg);	// Inside this function, the course is checked to be the current one
@@ -1121,7 +1122,7 @@ void Asg_HideAssignment (void)
 
    /***** Get assignment code *****/
    if ((Asg.AsgCod = Asg_GetParamAsgCod ()) <= 0)
-      Lay_WrongAssignmentExit ();
+      Err_WrongAssignmentExit ();
 
    /***** Get data of the assignment from database *****/
    Asg_GetDataOfAssignmentByCod (&Asg);
@@ -1158,7 +1159,7 @@ void Asg_ShowAssignment (void)
 
    /***** Get assignment code *****/
    if ((Asg.AsgCod = Asg_GetParamAsgCod ()) <= 0)
-      Lay_WrongAssignmentExit ();
+      Err_WrongAssignmentExit ();
 
    /***** Get data of the assignment from database *****/
    Asg_GetDataOfAssignmentByCod (&Asg);
@@ -1926,7 +1927,7 @@ unsigned Asg_GetNumCoursesWithAssignments (Hie_Lvl_Level_t Scope)
 			" WHERE CrsCod=%ld",
                         Gbl.Hierarchy.Crs.CrsCod);
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 return 0;
      }
   }
@@ -2014,20 +2015,20 @@ unsigned Asg_GetNumAssignments (Hie_Lvl_Level_t Scope,unsigned *NumNotif)
                          Gbl.Hierarchy.Crs.CrsCod);
          break;
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 break;
      }
 
    /***** Get number of assignments *****/
    row = mysql_fetch_row (mysql_res);
    if (sscanf (row[0],"%u",&NumAssignments) != 1)
-      Lay_ShowErrorAndExit ("Error when getting number of assignments.");
+      Err_ShowErrorAndExit ("Error when getting number of assignments.");
 
    /***** Get number of notifications by email *****/
    if (row[1])
      {
       if (sscanf (row[1],"%u",NumNotif) != 1)
-         Lay_ShowErrorAndExit ("Error when getting number of notifications of assignments.");
+         Err_ShowErrorAndExit ("Error when getting number of notifications of assignments.");
      }
    else
       *NumNotif = 0;
diff --git a/swad_attendance.c b/swad_attendance.c
index e62caa84..31943082 100644
--- a/swad_attendance.c
+++ b/swad_attendance.c
@@ -36,6 +36,7 @@
 #include "swad_attendance.h"
 #include "swad_box.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_group.h"
@@ -486,7 +487,7 @@ static void Att_ShowOneAttEvent (struct Att_Events *Events,
 	StartEndTime++)
      {
       if (asprintf (&Id,"att_date_%u_%u",(unsigned) StartEndTime,UniqueId) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       if (ShowOnlyThisAttEventComplete)
 	 HTM_TD_Begin ("id=\"%s\" class=\"%s LB\"",
 		       Id,
@@ -711,7 +712,7 @@ static void Att_GetListAttEvents (struct Att_Events *Events,
      {
       /***** Create list of attendance events *****/
       if ((Events->Lst = calloc (Events->Num,sizeof (*Events->Lst))) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
 
       /***** Get the attendance events codes *****/
       for (NumAttEvent = 0;
@@ -720,7 +721,7 @@ static void Att_GetListAttEvents (struct Att_Events *Events,
         {
          /* Get next attendance event code */
          if ((Events->Lst[NumAttEvent].AttCod = DB_GetNextCode (mysql_res)) < 0)
-            Lay_WrongEventExit ();
+            Err_WrongEventExit ();
         }
      }
 
@@ -739,10 +740,10 @@ static void Att_GetDataOfAttEventByCodAndCheckCrs (struct Att_Event *Event)
    if (Att_GetDataOfAttEventByCod (Event))
      {
       if (Event->CrsCod != Gbl.Hierarchy.Crs.CrsCod)
-         Lay_WrongEventExit ();
+         Err_WrongEventExit ();
      }
    else	// Attendance event not found
-      Lay_WrongEventExit ();
+      Err_WrongEventExit ();
   }
 
 /*****************************************************************************/
@@ -920,7 +921,7 @@ void Att_AskRemAttEvent (void)
 
    /***** Get attendance event code *****/
    if ((Event.AttCod = Att_GetParamAttCod ()) < 0)
-      Lay_WrongEventExit ();
+      Err_WrongEventExit ();
 
    /***** Get data of the attendance event from database *****/
    Att_GetDataOfAttEventByCodAndCheckCrs (&Event);
@@ -955,7 +956,7 @@ void Att_GetAndRemAttEvent (void)
 
    /***** Get attendance event code *****/
    if ((Event.AttCod = Att_GetParamAttCod ()) < 0)
-      Lay_WrongEventExit ();
+      Err_WrongEventExit ();
 
    /***** Get data of the attendance event from database *****/
    // Inside this function, the course is checked to be the current one
@@ -998,7 +999,7 @@ void Att_HideAttEvent (void)
 
    /***** Get attendance event code *****/
    if ((Event.AttCod = Att_GetParamAttCod ()) < 0)
-      Lay_WrongEventExit ();
+      Err_WrongEventExit ();
 
    /***** Get data of the attendance event from database *****/
    Att_GetDataOfAttEventByCodAndCheckCrs (&Event);
@@ -1026,7 +1027,7 @@ void Att_ShowAttEvent (void)
 
    /***** Get attendance event code *****/
    if ((Event.AttCod = Att_GetParamAttCod ()) < 0)
-      Lay_WrongEventExit ();
+      Err_WrongEventExit ();
 
    /***** Get data of the attendance event from database *****/
    Att_GetDataOfAttEventByCodAndCheckCrs (&Event);
@@ -1753,7 +1754,7 @@ unsigned Att_GetNumCoursesWithAttEvents (Hie_Lvl_Level_t Scope)
 			       " WHERE CrsCod=%ld",
 			       Gbl.Hierarchy.Crs.CrsCod);
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 return 0;	// Not reached
      }
   }
@@ -1825,20 +1826,20 @@ unsigned Att_GetNumAttEvents (Hie_Lvl_Level_t Scope,unsigned *NumNotif)
                          Gbl.Hierarchy.Crs.CrsCod);
          break;
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 break;
      }
 
    /***** Get number of attendance events *****/
    row = mysql_fetch_row (mysql_res);
    if (sscanf (row[0],"%u",&NumAttEvents) != 1)
-      Lay_ShowErrorAndExit ("Error when getting number of attendance events.");
+      Err_ShowErrorAndExit ("Error when getting number of attendance events.");
 
    /***** Get number of notifications by email *****/
    if (row[1])
      {
       if (sscanf (row[1],"%u",NumNotif) != 1)
-         Lay_ShowErrorAndExit ("Error when getting number of notifications of attendance events.");
+         Err_ShowErrorAndExit ("Error when getting number of notifications of attendance events.");
      }
    else
       *NumNotif = 0;
@@ -1862,7 +1863,7 @@ void Att_SeeOneAttEvent (void)
 
    /***** Get attendance event code *****/
    if ((Events.AttCod = Att_GetParamAttCod ()) < 0)
-      Lay_WrongEventExit ();
+      Err_WrongEventExit ();
 
    /***** Show event *****/
    Att_ShowEvent (&Events);
@@ -2097,7 +2098,7 @@ static void Att_WriteRowUsrToCallTheRoll (unsigned NumUsr,
 	 // A student can see only her/his attendance
 	 ItsMe = Usr_ItsMe (UsrDat->UsrCod);
 	 if (!ItsMe)
-	    Lay_ShowErrorAndExit ("Wrong call.");
+	    Err_ShowErrorAndExit ("Wrong call.");
 	 ICanChangeStdAttendance = false;
 	 ICanEditStdComment = Event->Open;	// Attendance event is open
 	 ICanEditTchComment = false;
@@ -2260,7 +2261,7 @@ static void Att_PutParamsCodGrps (long AttCod)
      {
       MaxLengthGrpCods = NumGrps * (1 + 20) - 1;
       if ((GrpCods = malloc (MaxLengthGrpCods + 1)) == NULL)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       GrpCods[0] = '\0';
 
       /* Get groups */
@@ -2307,7 +2308,7 @@ void Att_RegisterMeAsStdInAttEvent (void)
 
    /***** Get attendance event code *****/
    if ((Event.AttCod = Att_GetParamAttCod ()) < 0)
-      Lay_WrongEventExit ();
+      Err_WrongEventExit ();
    Att_GetDataOfAttEventByCodAndCheckCrs (&Event);	// This checks that event belong to current course
 
    if (Event.Open)
@@ -2372,7 +2373,7 @@ void Att_RegisterStudentsInAttEvent (void)
 
    /***** Get attendance event code *****/
    if ((Event.AttCod = Att_GetParamAttCod ()) < 0)
-      Lay_WrongEventExit ();
+      Err_WrongEventExit ();
    Att_GetDataOfAttEventByCodAndCheckCrs (&Event);	// This checks that event belong to current course
 
    /***** Get groups selected *****/
@@ -2739,7 +2740,7 @@ static void Att_ReqListOrPrintUsrsAttendanceCrs (void *TypeOfView)
 	 Att_FreeListAttEvents (&Events);
 	 break;
       default:
-	 Lay_WrongTypeOfViewExit ();
+	 Err_WrongTypeOfViewExit ();
 	 break;
      }
   }
@@ -2807,7 +2808,7 @@ static void Att_ListOrPrintMyAttendanceCrs (Att_TypeOfView_t TypeOfView)
 			     NULL,Box_NOT_CLOSABLE);
 	       break;
 	    default:
-	       Lay_WrongTypeOfViewExit ();
+	       Err_WrongTypeOfViewExit ();
 	       break;
 	   }
 
@@ -2837,7 +2838,7 @@ static void Att_ListOrPrintMyAttendanceCrs (Att_TypeOfView_t TypeOfView)
 	 Att_FreeListAttEvents (&Events);
 	 break;
       default:
-	 Lay_WrongTypeOfViewExit ();
+	 Err_WrongTypeOfViewExit ();
 	 break;
      }
   }
@@ -2923,7 +2924,7 @@ static void Att_ListOrPrintUsrsAttendanceCrs (void *TypeOfView)
 				NULL,Box_NOT_CLOSABLE);
 		  break;
 	       default:
-		  Lay_WrongTypeOfViewExit ();
+		  Err_WrongTypeOfViewExit ();
 	      }
 
 	    /***** List events to select *****/
@@ -2957,7 +2958,7 @@ static void Att_ListOrPrintUsrsAttendanceCrs (void *TypeOfView)
 	 Grp_FreeListCodSelectedGrps ();
 	 break;
       default:
-	 Lay_WrongTypeOfViewExit ();
+	 Err_WrongTypeOfViewExit ();
 	 break;
      }
   }
@@ -2982,7 +2983,7 @@ static void Att_GetListSelectedAttCods (struct Att_Events *Events)
    /***** Allocate memory for list of attendance events selected *****/
    MaxSizeListAttCodsSelected = (size_t) Events->Num * (Cns_MAX_DECIMAL_DIGITS_LONG + 1);
    if ((Events->StrAttCodsSelected = malloc (MaxSizeListAttCodsSelected + 1)) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Get parameter multiple with list of attendance events selected *****/
    Par_GetParMultiToText ("AttCods",Events->StrAttCodsSelected,MaxSizeListAttCodsSelected);
@@ -3241,7 +3242,7 @@ static void Att_ListEventsToSelect (const struct Att_Events *Events,
       HTM_TD_End ();
 
       if (asprintf (&Id,"att_date_start_%u",UniqueId) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       HTM_TD_Begin ("class=\"DAT LT COLOR%u\"",Gbl.RowEvenOdd);
       HTM_LABEL_Begin ("for=\"Event%u\"",NumAttEvent);
       HTM_SPAN_Begin ("id=\"%s\"",Id);
@@ -3684,7 +3685,7 @@ static void Att_ListAttEventsForAStd (const struct Att_Events *Events,
 	 HTM_TD_End ();
 
 	 if (asprintf (&Id,"att_date_start_%u_%u",NumUsr,UniqueId) < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 	 HTM_TD_Begin ("class=\"DAT LT COLOR%u\"",Gbl.RowEvenOdd);
 	 HTM_SPAN_Begin ("id=\"%s\"",Id);
 	 HTM_SPAN_End ();
diff --git a/swad_banner.c b/swad_banner.c
index 2a8c4966..bb1be0df 100644
--- a/swad_banner.c
+++ b/swad_banner.c
@@ -33,6 +33,7 @@
 #include "swad_box.h"
 #include "swad_constant.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_HTML.h"
@@ -311,7 +312,7 @@ static void Ban_GetListBanners (struct Ban_Banners *Banners,
 
       /***** Create list with banners *****/
       if ((Banners->Lst = calloc ((size_t) Banners->Num,sizeof (*Banners->Lst))) == NULL)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
 
       /***** Get the banners *****/
       for (NumBan = 0;
@@ -325,7 +326,7 @@ static void Ban_GetListBanners (struct Ban_Banners *Banners,
 
 	 /* Get banner code (row[0]) */
 	 if ((Ban->BanCod = Str_ConvertStrCodToLongCod (row[0])) <= 0)
-	    Lay_WrongBannerExit ();
+	    Err_WrongBannerExit ();
 
 	 /* Get if banner is hidden (row[1]) */
 	 Ban->Hidden = (row[1][0] == 'Y');
@@ -573,7 +574,7 @@ void Ban_RemoveBanner (void)
 
    /***** Get banner code *****/
    if ((Ban.BanCod = Ban_GetParamBanCod ()) <= 0)
-      Lay_WrongBannerExit ();
+      Err_WrongBannerExit ();
 
    /***** Get data of the banner from database *****/
    Ban_GetDataOfBannerByCod (&Ban);
@@ -637,7 +638,7 @@ static void Ban_ShowOrHideBanner (struct Ban_Banner *Ban,bool Hide)
   {
    /***** Get banner code *****/
    if ((Ban->BanCod = Ban_GetParamBanCod ()) <= 0)
-      Lay_WrongBannerExit ();
+      Err_WrongBannerExit ();
 
    /***** Get data of the banner from database *****/
    Ban_GetDataOfBannerByCod (Ban);
@@ -724,7 +725,7 @@ static void Ban_RenameBanner (struct Ban_Banner *Ban,
    /***** Get parameters from form *****/
    /* Get the code of the banner */
    if ((Ban->BanCod = Ban_GetParamBanCod ()) <= 0)
-      Lay_WrongBannerExit ();
+      Err_WrongBannerExit ();
 
    /* Get the new name for the banner */
    Par_GetParToText (ParamName,NewBanName,MaxBytes);
@@ -816,7 +817,7 @@ void Ban_ChangeBannerImg (void)
    /***** Get parameters from form *****/
    /* Get the code of the banner */
    if ((Ban.BanCod = Ban_GetParamBanCod ()) <= 0)
-      Lay_WrongBannerExit ();
+      Err_WrongBannerExit ();
 
    /* Get the new WWW for the banner */
    Par_GetParToText ("Img",NewImg,Ban_MAX_BYTES_IMAGE);
@@ -867,7 +868,7 @@ void Ban_ChangeBannerWWW (void)
    /***** Get parameters from form *****/
    /* Get the code of the banner */
    if ((Ban.BanCod = Ban_GetParamBanCod ()) <= 0)
-      Lay_WrongBannerExit ();
+      Err_WrongBannerExit ();
 
    /* Get the new WWW for the banner */
    Par_GetParToText ("WWW",NewWWW,Cns_MAX_BYTES_WWW);
@@ -1156,7 +1157,7 @@ void Ban_ClickOnBanner (void)
 
    /***** Get banner code *****/
    if ((Ban.BanCod = Ban_GetParamBanCod ()) <= 0)
-      Lay_WrongBannerExit ();
+      Err_WrongBannerExit ();
 
    /***** Get data of the banner from database *****/
    Ban_GetDataOfBannerByCod (&Ban);
diff --git a/swad_box.c b/swad_box.c
index e0e9905b..b1e720c9 100644
--- a/swad_box.c
+++ b/swad_box.c
@@ -30,6 +30,7 @@
 
 #include "swad_action.h"
 #include "swad_box.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_help.h"
@@ -124,7 +125,7 @@ static void Box_BoxInternalBegin (const char *Width,const char *Title,
 
    /***** Check level of nesting *****/
    if (Gbl.Box.Nested >= Box_MAX_NESTED - 1)	// Can not nest a new box
-      Lay_ShowErrorAndExit ("Box nesting limit reached.");
+      Err_ShowErrorAndExit ("Box nesting limit reached.");
 
    /***** Increase level of nesting *****/
    Gbl.Box.Nested++;
@@ -133,7 +134,7 @@ static void Box_BoxInternalBegin (const char *Width,const char *Title,
    if (Closable == Box_CLOSABLE)
      {
       if ((Gbl.Box.Ids[Gbl.Box.Nested] = malloc (Frm_MAX_BYTES_ID + 1)) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
      }
    else
       Gbl.Box.Ids[Gbl.Box.Nested] = NULL;
@@ -224,7 +225,7 @@ void Box_BoxEnd (void)
   {
    /***** Check level of nesting *****/
    if (Gbl.Box.Nested < 0)
-      Lay_ShowErrorAndExit ("Trying to end a box not open.");
+      Err_ShowErrorAndExit ("Trying to end a box not open.");
 
    /***** Free memory allocated for box id string *****/
    if (Gbl.Box.Ids[Gbl.Box.Nested])
diff --git a/swad_building.c b/swad_building.c
index a9d6b71c..6aaec5f2 100644
--- a/swad_building.c
+++ b/swad_building.c
@@ -32,6 +32,7 @@
 #include "swad_box.h"
 #include "swad_building.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_HTML.h"
@@ -355,7 +356,7 @@ void Bld_GetListBuildings (struct Bld_Buildings *Buildings,
      {
       /***** Create list with courses in center *****/
       if ((Buildings->Lst = calloc ((size_t) Buildings->Num,sizeof (*Buildings->Lst))) == NULL)
-          Lay_NotEnoughMemoryExit ();
+          Err_NotEnoughMemoryExit ();
 
       /***** Get the buildings *****/
       for (NumBuilding = 0;
@@ -369,7 +370,7 @@ void Bld_GetListBuildings (struct Bld_Buildings *Buildings,
 
          /* Get building code (row[0]) */
          if ((Building->BldCod = Str_ConvertStrCodToLongCod (row[0])) <= 0)
-            Lay_WrongBuildingExit ();
+            Err_WrongBuildingExit ();
 
          /* Get the short name of the building (row[1]) */
          Str_Copy (Building->ShrtName,row[1],sizeof (Building->ShrtName) - 1);
@@ -552,7 +553,7 @@ void Bld_RemoveBuilding (void)
 
    /***** Get building code *****/
    if ((Bld_EditingBuilding->BldCod = Bld_GetParamBldCod ()) <= 0)
-      Lay_WrongBuildingExit ();
+      Err_WrongBuildingExit ();
 
    /***** Get data of the building from database *****/
    Bld_GetDataOfBuildingByCod (Bld_EditingBuilding);
@@ -649,7 +650,7 @@ static void Bld_RenameBuilding (Cns_ShrtOrFullName_t ShrtOrFullName)
    /***** Get parameters from form *****/
    /* Get the code of the building */
    if ((Bld_EditingBuilding->BldCod = Bld_GetParamBldCod ()) <= 0)
-      Lay_WrongBuildingExit ();
+      Err_WrongBuildingExit ();
 
    /* Get the new name for the building */
    Par_GetParToText (ParamName,NewClaName,MaxBytes);
@@ -742,7 +743,7 @@ void Bld_ChangeBuildingLocation (void)
    /***** Get parameters from form *****/
    /* Get the code of the building */
    if ((Bld_EditingBuilding->BldCod = Bld_GetParamBldCod ()) <= 0)
-      Lay_WrongBuildingExit ();
+      Err_WrongBuildingExit ();
 
    /* Get the new location for the building */
    Par_GetParToText ("Location",NewLocation,Bld_MAX_BYTES_LOCATION);
@@ -942,11 +943,11 @@ static void Bld_EditingBuildingConstructor (void)
   {
    /***** Pointer must be NULL *****/
    if (Bld_EditingBuilding != NULL)
-      Lay_WrongBuildingExit ();
+      Err_WrongBuildingExit ();
 
    /***** Allocate memory for building *****/
    if ((Bld_EditingBuilding = malloc (sizeof (*Bld_EditingBuilding))) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Reset building *****/
    Bld_EditingBuilding->BldCod      = -1L;
diff --git a/swad_call_for_exam.c b/swad_call_for_exam.c
index e1404bcf..767e1bdd 100644
--- a/swad_call_for_exam.c
+++ b/swad_call_for_exam.c
@@ -35,6 +35,7 @@
 #include "swad_call_for_exam.h"
 #include "swad_config.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_hierarchy.h"
@@ -262,25 +263,25 @@ static long Cfe_GetParamsCallsForExams (struct Cfe_CallsForExams *CallsForExams)
 static void Cfe_AllocMemCallForExam (struct Cfe_CallsForExams *CallsForExams)
   {
    if ((CallsForExams->CallForExam.Place       = malloc (Cns_MAX_BYTES_TEXT + 1)) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    if ((CallsForExams->CallForExam.Mode        = malloc (Cns_MAX_BYTES_TEXT + 1)) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    if ((CallsForExams->CallForExam.Structure   = malloc (Cns_MAX_BYTES_TEXT + 1)) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    if ((CallsForExams->CallForExam.DocRequired = malloc (Cns_MAX_BYTES_TEXT + 1)) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    if ((CallsForExams->CallForExam.MatRequired = malloc (Cns_MAX_BYTES_TEXT + 1)) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    if ((CallsForExams->CallForExam.MatAllowed  = malloc (Cns_MAX_BYTES_TEXT + 1)) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    if ((CallsForExams->CallForExam.OtherInfo   = malloc (Cns_MAX_BYTES_TEXT + 1)) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
   }
 
 /*****************************************************************************/
@@ -424,7 +425,7 @@ void Cfe_PrintCallForExam (void)
 
    /***** Get the code of the call for exam *****/
    if ((ExaCod = Cfe_GetParamExaCod ()) <= 0)
-      Lay_WrongCallForExamExit ();
+      Err_WrongCallForExamExit ();
 
    /***** Read call for exam from the database *****/
    Cfe_GetDataCallForExamFromDB (&CallsForExams,ExaCod);
@@ -453,7 +454,7 @@ void Cfe_ReqRemoveCallForExam (void)
 
    /***** Get the code of the call for exam *****/
    if ((ExaCod = Cfe_GetParamExaCod ()) <= 0)
-      Lay_WrongCallForExamExit ();
+      Err_WrongCallForExamExit ();
 
    /***** Show question and button to remove call for exam *****/
    /* Begin alert */
@@ -489,7 +490,7 @@ void Cfe_RemoveCallForExam1 (void)
 
    /***** Get the code of the call for exam *****/
    if ((ExaCod = Cfe_GetParamExaCod ()) <= 0)
-      Lay_WrongCallForExamExit ();
+      Err_WrongCallForExamExit ();
 
    /***** Mark the call for exam as deleted in the database *****/
    DB_QueryUPDATE ("can not remove call for exam",
@@ -538,7 +539,7 @@ void Cfe_HideCallForExam (void)
 
    /***** Get the code of the call for exam *****/
    if ((ExaCod = Cfe_GetParamExaCod ()) <= 0)
-      Lay_WrongCallForExamExit ();
+      Err_WrongCallForExamExit ();
 
    /***** Mark the call for exam as hidden in the database *****/
    DB_QueryUPDATE ("can not hide call for exam",
@@ -570,7 +571,7 @@ void Cfe_UnhideCallForExam (void)
 
    /***** Get the code of the call for exam *****/
    if ((ExaCod = Cfe_GetParamExaCod ()) <= 0)
-      Lay_WrongCallForExamExit ();
+      Err_WrongCallForExamExit ();
 
    /***** Mark the call for exam as visible in the database *****/
    DB_QueryUPDATE ("can not unhide call for exam",
@@ -737,7 +738,7 @@ static void Cfe_ListCallsForExams (struct Cfe_CallsForExams *CallsForExams,
      {
       /***** Get the code of the call for exam (row[0]) *****/
       if ((ExaCod = DB_GetNextCode (mysql_res)) <= 0)
-         Lay_WrongCallForExamExit ();
+         Err_WrongCallForExamExit ();
 
       /***** Allocate memory for the call for exam *****/
       Cfe_AllocMemCallForExam (CallsForExams);
@@ -921,7 +922,7 @@ void Cfe_CreateListCallsForExams (struct Cfe_CallsForExams *CallsForExams)
 	{
 	 /***** Allocate memory for the list *****/
 	 if ((CallsForExams->Lst = calloc (NumExaAnns,sizeof (*CallsForExams->Lst))) == NULL)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Get the dates of the existing calls for exams *****/
 	 for (NumExaAnn = 0;
@@ -939,7 +940,7 @@ void Cfe_CreateListCallsForExams (struct Cfe_CallsForExams *CallsForExams)
 			&CallsForExams->Lst[CallsForExams->NumCallsForExams].ExamDate.Year,
 			&CallsForExams->Lst[CallsForExams->NumCallsForExams].ExamDate.Month,
 			&CallsForExams->Lst[CallsForExams->NumCallsForExams].ExamDate.Day) != 3)
-	       Lay_WrongCallForExamExit ();
+	       Err_WrongCallForExamExit ();
 
 	    /***** Increment number of elements in list *****/
 	    CallsForExams->NumCallsForExams++;
@@ -999,7 +1000,7 @@ static void Cfe_GetDataCallForExamFromDB (struct Cfe_CallsForExams *CallsForExam
 			" FROM cfe_exams"
 		       " WHERE ExaCod=%ld",
 		       ExaCod) != 1)
-      Lay_WrongCallForExamExit ();
+      Err_WrongCallForExamExit ();
 
    /***** Get the data of the call for exam *****/
    row = mysql_fetch_row (mysql_res);
@@ -1009,9 +1010,9 @@ static void Cfe_GetDataCallForExamFromDB (struct Cfe_CallsForExams *CallsForExam
 
    /* Status of the call for exam (row[1]) */
    if (sscanf (row[1],"%u",&UnsignedNum) != 1)
-      Lay_WrongCallForExamExit ();
+      Err_WrongCallForExamExit ();
    if (UnsignedNum >= Cfe_NUM_STATUS)
-      Lay_WrongCallForExamExit ();
+      Err_WrongCallForExamExit ();
    CallsForExams->CallForExam.Status = (Cfe_Status_t) UnsignedNum;
 
    /* Name of the course (row[2]) */
@@ -1020,7 +1021,7 @@ static void Cfe_GetDataCallForExamFromDB (struct Cfe_CallsForExams *CallsForExam
 
    /* Year (row[3]) */
    if (sscanf (row[3],"%u",&CallsForExams->CallForExam.Year) != 1)
-      Lay_WrongCallForExamExit ();
+      Err_WrongCallForExamExit ();
 
    /* Exam session (row[4]) */
    Str_Copy (CallsForExams->CallForExam.Session,row[4],
@@ -1034,7 +1035,7 @@ static void Cfe_GetDataCallForExamFromDB (struct Cfe_CallsForExams *CallsForExam
                &Hour,
 	       &Minute,
 	       &Second) != 6)
-      Lay_WrongCallForExamExit ();
+      Err_WrongCallForExamExit ();
 
    /* Date of exam (row[6]) */
    if (sscanf (row[6],"%04u-%02u-%02u %02u:%02u:%02u",
@@ -1044,7 +1045,7 @@ static void Cfe_GetDataCallForExamFromDB (struct Cfe_CallsForExams *CallsForExam
                &CallsForExams->CallForExam.StartTime.Hour,
 	       &CallsForExams->CallForExam.StartTime.Minute,
 	       &Second) != 6)
-      Lay_WrongCallForExamExit ();
+      Err_WrongCallForExamExit ();
    snprintf (CallsForExams->CallForExam.ExamDate.YYYYMMDD,
              sizeof (CallsForExams->CallForExam.ExamDate.YYYYMMDD),"%04u%02u%02u",
              CallsForExams->CallForExam.ExamDate.Year,
@@ -1056,7 +1057,7 @@ static void Cfe_GetDataCallForExamFromDB (struct Cfe_CallsForExams *CallsForExam
                &CallsForExams->CallForExam.Duration.Hour,
                &CallsForExams->CallForExam.Duration.Minute,
                &Second) != 3)
-      Lay_WrongCallForExamExit ();
+      Err_WrongCallForExamExit ();
 
    /* Place (row[8]), exam mode (row[9]), structure (row[10]),
       documentation required (row[11]), material required (row[12]),
@@ -1837,5 +1838,5 @@ static void Cfe_GetNotifContentCallForExam (const struct Cfe_CallsForExams *Call
                  Txt_CALL_FOR_EXAM_Material_required,CallsForExams->CallForExam.MatRequired,
                  Txt_CALL_FOR_EXAM_Material_allowed,CallsForExams->CallForExam.MatAllowed,
                  Txt_CALL_FOR_EXAM_Other_information,CallsForExams->CallForExam.OtherInfo) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
   }
diff --git a/swad_center.c b/swad_center.c
index 69f0e1f2..d8ee046d 100644
--- a/swad_center.c
+++ b/swad_center.c
@@ -33,6 +33,7 @@
 #include "swad_center.h"
 #include "swad_center_config.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_figure.h"
 #include "swad_figure_cache.h"
 #include "swad_form.h"
@@ -577,7 +578,7 @@ void Ctr_GetBasicListOfCenters (long InsCod)
       /***** Create list with courses in degree *****/
       if ((Gbl.Hierarchy.Ctrs.Lst = calloc ((size_t) Gbl.Hierarchy.Ctrs.Num,
                                             sizeof (*Gbl.Hierarchy.Ctrs.Lst))) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
 
       /***** Get the centers *****/
       for (NumCtr = 0;
@@ -663,7 +664,7 @@ void Ctr_GetFullListOfCenters (long InsCod)
       /***** Create list with courses in degree *****/
       if ((Gbl.Hierarchy.Ctrs.Lst = calloc ((size_t) Gbl.Hierarchy.Ctrs.Num,
                                             sizeof (*Gbl.Hierarchy.Ctrs.Lst))) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
 
       /***** Get the centers *****/
       for (NumCtr = 0;
@@ -750,7 +751,7 @@ static void Ctr_GetDataOfCenterFromRow (struct Ctr_Center *Ctr,MYSQL_ROW row)
   {
    /***** Get center code (row[0]) *****/
    if ((Ctr->CtrCod = Str_ConvertStrCodToLongCod (row[0])) <= 0)
-      Lay_WrongCenterExit ();
+      Err_WrongCenterExit ();
 
    /***** Get institution code (row[1]) *****/
    Ctr->InsCod = Str_ConvertStrCodToLongCod (row[1]);
@@ -760,7 +761,7 @@ static void Ctr_GetDataOfCenterFromRow (struct Ctr_Center *Ctr,MYSQL_ROW row)
 
    /***** Get center status (row[3]) *****/
    if (sscanf (row[3],"%u",&(Ctr->Status)) != 1)
-      Lay_WrongStatusExit ();
+      Err_WrongStatusExit ();
 
    /***** Get requester user's code (row[4]) *****/
    Ctr->RequesterUsrCod = Str_ConvertStrCodToLongCod (row[4]);
@@ -881,7 +882,7 @@ void Ctr_WriteSelectorOfCenter (void)
 
          /* Get center code (row[0]) */
          if ((CtrCod = Str_ConvertStrCodToLongCod (row[0])) < 0)
-            Lay_WrongCenterExit ();
+            Err_WrongCenterExit ();
 
          /* Write option */
 	 HTM_OPTION (HTM_Type_LONG,&CtrCod,
@@ -1185,7 +1186,7 @@ long Ctr_GetAndCheckParamOtherCtrCod (long MinCodAllowed)
 
    /***** Get and check parameter with code of center *****/
    if ((CtrCod = Par_GetParToLong ("OthCtrCod")) < MinCodAllowed)
-      Lay_WrongCenterExit ();
+      Err_WrongCenterExit ();
 
    return CtrCod;
   }
@@ -1518,7 +1519,7 @@ void Ctr_ChangeCtrStatus (void)
 				      (unsigned long) Ctr_MAX_STATUS,
 				      (unsigned long) Ctr_WRONG_STATUS);
    if (Status == Ctr_WRONG_STATUS)
-      Lay_WrongStatusExit ();
+      Err_WrongStatusExit ();
    StatusTxt = Ctr_GetStatusTxtFromStatusBits (Status);
    Status = Ctr_GetStatusBitsFromStatusTxt (StatusTxt);	// New status
 
@@ -1603,7 +1604,7 @@ static void Ctr_PutFormToCreateCenter (const struct Plc_Places *Places)
    else if (Gbl.Usrs.Me.Role.Max >= Rol_GST)
       Frm_BeginForm (ActReqCtr);
    else
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Begin box and table *****/
    Box_BoxTableBegin (NULL,Txt_New_center,
@@ -2283,11 +2284,11 @@ static void Ctr_EditingCenterConstructor (void)
   {
    /***** Pointer must be NULL *****/
    if (Ctr_EditingCtr != NULL)
-      Lay_WrongCenterExit ();
+      Err_WrongCenterExit ();
 
    /***** Allocate memory for center *****/
    if ((Ctr_EditingCtr = malloc (sizeof (*Ctr_EditingCtr))) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Reset center *****/
    Ctr_EditingCtr->CtrCod          = -1L;
diff --git a/swad_center_config.c b/swad_center_config.c
index 1d924aaf..e0560180 100644
--- a/swad_center_config.c
+++ b/swad_center_config.c
@@ -35,6 +35,7 @@
 
 #include "swad_center.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_figure_cache.h"
 #include "swad_form.h"
 #include "swad_global.h"
@@ -464,10 +465,10 @@ static void CtrCfg_Photo (bool PrintView,bool PutForm,bool PutLink,
 		 Cfg_URL_CTR_PUBLIC,
 		 (unsigned) (Gbl.Hierarchy.Ctr.CtrCod % 100),
 		 (unsigned) Gbl.Hierarchy.Ctr.CtrCod) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    if (asprintf (&Icon,"%u.jpg",
 		 (unsigned) Gbl.Hierarchy.Ctr.CtrCod) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    HTM_IMG (URL,Icon,Gbl.Hierarchy.Ctr.FullName,
 	    "class=\"%s\"",PrintView ? "CENTER_PHOTO_PRINT CENTER_PHOTO_WIDTH" :
 				       "CENTER_PHOTO_SHOW CENTER_PHOTO_WIDTH");
@@ -531,7 +532,7 @@ static void CtrCfg_GetPhotoAttr (long CtrCod,char **PhotoAttribution)
 	   {
 	    Length = strlen (row[0]);
 	    if (((*PhotoAttribution) = malloc (Length + 1)) == NULL)
-               Lay_NotEnoughMemoryExit ();
+               Err_NotEnoughMemoryExit ();
 	    Str_Copy (*PhotoAttribution,row[0],Length);
 	   }
      }
@@ -970,7 +971,7 @@ void CtrCfg_ReceivePhoto (void)
              PathFileImg);
    ReturnCode = system (Command);
    if (ReturnCode == -1)
-      Lay_ShowErrorAndExit ("Error when running command to process image.");
+      Err_ShowErrorAndExit ("Error when running command to process image.");
 
    /***** Write message depending on return code *****/
    ReturnCode = WEXITSTATUS(ReturnCode);
@@ -980,7 +981,7 @@ void CtrCfg_ReceivePhoto (void)
 	        "Image could not be processed successfully.<br />"
 		"Error code returned by the program of processing: %d",
 	        ReturnCode);
-      Lay_ShowErrorAndExit (ErrorMsg);
+      Err_ShowErrorAndExit (ErrorMsg);
      }
 
    /***** Remove temporary file *****/
diff --git a/swad_changelog.h b/swad_changelog.h
index 47eb5964..6d7e69d4 100644
--- a/swad_changelog.h
+++ b/swad_changelog.h
@@ -600,13 +600,14 @@ TODO: Salvador Romero Cort
 
 TODO: FIX BUG, URGENT! En las fechas como parámetro Dat_WriteParamsIniEndDates(), por ejemplo al cambiar el color de la gráfica de accesos por día y hora, no se respeta la zona horaria.
 */
-#define Log_PLATFORM_VERSION	"SWAD 20.67.11 (2021-04-26)"
+#define Log_PLATFORM_VERSION	"SWAD 20.68 (2021-04-26)"
 #define CSS_FILE		"swad20.45.css"
 #define JS_FILE			"swad20.6.2.js"
 /*
 TODO: Rename CENTRE to CENTER in help wiki.
 TODO: Rename ASSESSMENT.Announcements to ASSESSMENT.Calls_for_exams
 
+	Version 20.68:    Apr 26, 2021  New module swad_error. (309853 lines)
 	Version 20.67.11: Apr 26, 2021  Fixed bug in departments. (309677 lines)
 	Version 20.67.10: Apr 25, 2021  Fixed bug in notification about new assignment, reported by Eva Martínez Ortigosa. (? lines)
 	Version 20.67.9:  Apr 25, 2021  Fixed bug in users' works, reported by Eva Martínez Ortigosa. (309675 lines)
diff --git a/swad_chat.c b/swad_chat.c
index 1991a279..c442af10 100644
--- a/swad_chat.c
+++ b/swad_chat.c
@@ -33,6 +33,7 @@
 #include "swad_chat.h"
 #include "swad_config.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_HTML.h"
@@ -176,7 +177,7 @@ void Cht_ShowListOfAvailableChatRooms (void)
       /* Get data of this degree */
       Deg.DegCod = Gbl.Usrs.Me.MyDegs.Degs[NumMyDeg].DegCod;
       if (!Deg_GetDataOfDegreeByCod (&Deg))
-         Lay_WrongDegreeExit ();
+         Err_WrongDegreeExit ();
 
       /* Link to the room of this degree */
       IsLastItemInLevel[1] = (NumMyDeg == Gbl.Usrs.Me.MyDegs.Num - 1);
@@ -399,9 +400,9 @@ void Cht_OpenChatWindow (void)
    Par_GetParToText ("RoomFullName",RoomFullName,Cht_MAX_BYTES_ROOM_FULL_NAME);
 
    if (!RoomCode[0] || !RoomShrtName[0] || !RoomFullName[0])
-      Lay_ShowErrorAndExit ("Wrong code or name of chat room.");
+      Err_ShowErrorAndExit ("Wrong code or name of chat room.");
    if (strcspn (RoomCode," \t\n\r") != strlen (RoomCode)) // If RoomCode contiene espacios
-      Lay_ShowErrorAndExit ("Wrong code of chat room.");
+      Err_ShowErrorAndExit ("Wrong code of chat room.");
 
    /***** Fill the lists with the degrees and courses I belong to *****/ 
    Usr_GetMyDegrees ();
@@ -521,7 +522,7 @@ void Cht_OpenChatWindow (void)
 
    /***** Open index.html file with the HTML page for the chat *****/
    if ((FileChat = fopen (Cfg_PATH_AND_FILE_REL_CHAT_PRIVATE,"rb")) == NULL)
-      Lay_ShowErrorAndExit ("Can not open chat.");
+      Err_ShowErrorAndExit ("Can not open chat.");
 
    /***** Start writing the index.html file to the output *****/
    HTM_Txt ("Content-type: text/html; charset=windows-1252\n\n");	// Two carriage returns at the end of the line are mandatory!
diff --git a/swad_config.c b/swad_config.c
index b5efecff..88ca3d18 100644
--- a/swad_config.c
+++ b/swad_config.c
@@ -31,6 +31,7 @@
 #include <string.h>		// For strcasecmp...
 
 #include "swad_config.h"
+#include "swad_error.h"
 #include "swad_global.h"
 #include "swad_layout.h"
 #include "swad_string.h"
@@ -78,7 +79,7 @@ void Cfg_GetConfigFromFile (void)
    /***** Read config from file to string *****/
    /* Open config file */
    if ((FileCfg = fopen (Cfg_FILE_CONFIG,"rb")) == NULL)
-      Lay_ShowErrorAndExit ("Can not open config file.");
+      Err_ShowErrorAndExit ("Can not open config file.");
 
    /* Compute file size */
    fseek (FileCfg,0L,SEEK_END);
@@ -89,14 +90,14 @@ void Cfg_GetConfigFromFile (void)
    if ((Config = malloc (Length + 1)) == NULL)
      {
       fclose (FileCfg);
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
      }
 
    /* Copy file content into buffer */
    if (fread (Config,sizeof (char),Length,FileCfg) != Length)
      {
       fclose (FileCfg);
-      Lay_ShowErrorAndExit ("Can not read config.");
+      Err_ShowErrorAndExit ("Can not read config.");
      }
    Config[Length] = '\0';
 
@@ -116,5 +117,5 @@ void Cfg_GetConfigFromFile (void)
 
    if (!Gbl.Config.DatabasePassword[0] ||
        !Gbl.Config.SMTPPassword[0])
-      Lay_ShowErrorAndExit ("Bad config format.");
+      Err_ShowErrorAndExit ("Bad config format.");
   }
diff --git a/swad_connected.c b/swad_connected.c
index cd0684e6..b86e512d 100644
--- a/swad_connected.c
+++ b/swad_connected.c
@@ -35,6 +35,7 @@
 
 #include "swad_box.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_hierarchy_level.h"
@@ -104,7 +105,7 @@ void Con_ShowConnectedUsrs (void)
    if (asprintf (&Title,"%s"
 	                "<div id=\"connected_current_time\"></div>",
 	         Txt_Connected_users) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    Box_BoxBegin (NULL,Title,
                  Con_PutIconToUpdateConnected,NULL,
 		 Hlp_USERS_Connected,Box_NOT_CLOSABLE);
@@ -597,7 +598,7 @@ static void Con_GetNumConnectedUsrsWithARoleBelongingCurrentLocation (Rol_Role_t
 			       Gbl.Hierarchy.Crs.CrsCod);
 	       break;
 	    default:
-	       Lay_WrongScopeExit ();
+	       Err_WrongScopeExit ();
 	       break;
 	   }
 	 break;
@@ -741,12 +742,12 @@ static void Con_GetNumConnectedUsrsWithARoleBelongingCurrentLocation (Rol_Role_t
 			       (unsigned) Role);
 	       break;
 	    default:
-	       Lay_WrongScopeExit ();
+	       Err_WrongScopeExit ();
 	       break;
 	   }
 	 break;
       default:
-	 Lay_WrongRoleExit ();
+	 Err_WrongRoleExit ();
 	 break;
      }
 
@@ -754,11 +755,11 @@ static void Con_GetNumConnectedUsrsWithARoleBelongingCurrentLocation (Rol_Role_t
 
    /***** Get number of users (row[0]) *****/
    if (sscanf (row[0],"%u",&(Usrs->NumUsrs)) != 1)
-      Lay_ShowErrorAndExit ("Error when getting number of connected users who belong to this location.");
+      Err_ShowErrorAndExit ("Error when getting number of connected users who belong to this location.");
 
    /***** Get number of distinct sexs (row[1]) *****/
    if (sscanf (row[1],"%u",&NumSexs) != 1)
-      Lay_ShowErrorAndExit ("Error when getting number of sexs in connected users who belong to this location.");
+      Err_ShowErrorAndExit ("Error when getting number of sexs in connected users who belong to this location.");
 
    /***** Get users' sex (row[2]) *****/
    Usrs->Sex = Usr_SEX_UNKNOWN;
@@ -910,7 +911,7 @@ static void Con_WriteRowConnectedUsrOnRightColumn (Rol_Role_t Role)
 	 Frm_BeginFormUnique (ActSeeRecOneTch);
 	 break;
       default:
-	 Lay_WrongRoleExit ();
+	 Err_WrongRoleExit ();
 	 break;
      }
    Usr_PutParamUsrCodEncrypted (UsrDat->EnUsrCod);
@@ -1111,12 +1112,12 @@ static void Con_ShowConnectedUsrsCurrentLocationOneByOneOnMainZone (Rol_Role_t R
 			       (unsigned) Role);
 	       break;
 	    default:
-	       Lay_WrongScopeExit ();
+	       Err_WrongScopeExit ();
 	       break;
 	   }
 	 break;
       default:
-	 Lay_WrongRoleExit ();
+	 Err_WrongRoleExit ();
 	 break;
      }
    if (NumUsrs)
@@ -1176,7 +1177,7 @@ static void Con_ShowConnectedUsrsCurrentLocationOneByOneOnMainZone (Rol_Role_t R
 		     Frm_BeginForm (ActSeeRecOneTch);
 		     break;
 		  default:
-		     Lay_WrongRoleExit ();
+		     Err_WrongRoleExit ();
 		 }
 	       Usr_PutParamUsrCodEncrypted (UsrDat.EnUsrCod);
 	      }
diff --git a/swad_country.c b/swad_country.c
index a5802875..b5aba60d 100644
--- a/swad_country.c
+++ b/swad_country.c
@@ -34,6 +34,7 @@
 
 #include "swad_country_config.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_figure.h"
 #include "swad_figure_cache.h"
 #include "swad_form.h"
@@ -564,7 +565,7 @@ void Cty_DrawCountryMap (struct Cty_Countr *Cty,const char *Class)
       if (asprintf (&URL,"%s/%s",
 		    Cfg_URL_ICON_COUNTRIES_PUBLIC,
 	            Cty->Alpha2) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       HTM_IMG (URL,Str_BuildStringStr ("%s.png",Cty->Alpha2),
 	       Cty->Name[Gbl.Prefs.Language],
 	       "class=\"%s\"",Class);
@@ -772,7 +773,7 @@ void Cty_GetBasicListOfCountries (void)
       /***** Create list with countries *****/
       if ((Gbl.Hierarchy.Ctys.Lst = calloc ((size_t) Gbl.Hierarchy.Ctys.Num,
                                             sizeof (*Gbl.Hierarchy.Ctys.Lst))) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
 
       /***** Get the countries *****/
       for (NumCty = 0;
@@ -786,7 +787,7 @@ void Cty_GetBasicListOfCountries (void)
 
          /* Get numerical country code (row[0]) */
          if ((Cty->CtyCod = Str_ConvertStrCodToLongCod (row[0])) < 0)
-            Lay_WrongCountrExit ();
+            Err_WrongCountrExit ();
 
          /* Get Alpha-2 country code (row[1]) */
          Str_Copy (Cty->Alpha2,row[1],sizeof (Cty->Alpha2) - 1);
@@ -862,7 +863,7 @@ void Cty_GetFullListOfCountries (void)
    /* Build order subquery */
    if (asprintf (&OrderBySubQuery,OrderBySubQueryFmt[Gbl.Hierarchy.Ctys.SelectedOrder],
 		 Lan_STR_LANG_ID[Gbl.Prefs.Language]) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /* Query database */
    Gbl.Hierarchy.Ctys.Num = (unsigned)
@@ -898,7 +899,7 @@ void Cty_GetFullListOfCountries (void)
       /***** Create list with countries *****/
       if ((Gbl.Hierarchy.Ctys.Lst = calloc ((size_t) Gbl.Hierarchy.Ctys.Num,
                                             sizeof (*Gbl.Hierarchy.Ctys.Lst))) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
 
       /***** Get the countries *****/
       for (NumCty = 0;
@@ -912,7 +913,7 @@ void Cty_GetFullListOfCountries (void)
 
          /* Get numerical country code (row[0]) */
          if ((Cty->CtyCod = Str_ConvertStrCodToLongCod (row[0])) < 0)
-            Lay_WrongCountrExit ();
+            Err_WrongCountrExit ();
 
          /* Get Alpha-2 country code (row[1]) */
          Str_Copy (Cty->Alpha2,row[1],sizeof (Cty->Alpha2) - 1);
@@ -981,7 +982,7 @@ void Cty_WriteSelectorOfCountry (void)
 
       /* Get country code (row[0]) */
       if ((CtyCod = Str_ConvertStrCodToLongCod (row[0])) < 0)
-         Lay_WrongCountrExit ();
+         Err_WrongCountrExit ();
 
       /* Write option */
       HTM_OPTION (HTM_Type_LONG,&CtyCod,
@@ -1302,7 +1303,7 @@ long Cty_GetAndCheckParamOtherCtyCod (long MinCodAllowed)
 
    /***** Get and check parameter with code of country *****/
    if ((CtyCod = Cty_GetParamOtherCtyCod ()) < MinCodAllowed)
-      Lay_WrongCountrExit ();
+      Err_WrongCountrExit ();
 
    return CtyCod;
   }
@@ -2119,11 +2120,11 @@ static void Cty_EditingCountryConstructor (void)
 
    /***** Pointer must be NULL *****/
    if (Cty_EditingCty != NULL)
-      Lay_WrongCountrExit ();
+      Err_WrongCountrExit ();
 
    /***** Allocate memory for country *****/
    if ((Cty_EditingCty = malloc (sizeof (*Cty_EditingCty))) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Reset country *****/
    Cty_EditingCty->CtyCod = -1L;
diff --git a/swad_country_config.c b/swad_country_config.c
index d1d31c6b..06c9e9fa 100644
--- a/swad_country_config.c
+++ b/swad_country_config.c
@@ -33,6 +33,7 @@
 #include <string.h>		// For string functions
 
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_figure_cache.h"
 #include "swad_form.h"
 #include "swad_global.h"
@@ -257,7 +258,7 @@ static void CtyCfg_GetCoordAndZoom (struct Coordinates *Coord,unsigned *Zoom)
 		   " AND ctr_centers.Latitude<>0"
 		   " AND ctr_centers.Longitude<>0",
 		 Gbl.Hierarchy.Cty.CtyCod) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    Map_GetCoordAndZoom (Coord,Zoom,Query);
    free (Query);
   }
@@ -593,7 +594,7 @@ static void CtyCfg_GetMapAttr (long CtyCod,char **MapAttribution)
 	   {
 	    Length = strlen (row[0]);
 	    if ((*MapAttribution = malloc (Length + 1)) == NULL)
-               Lay_NotEnoughMemoryExit ();
+               Err_NotEnoughMemoryExit ();
 	    Str_Copy (*MapAttribution,row[0],Length);
 	   }
      }
diff --git a/swad_course.c b/swad_course.c
index 1eefff26..378b502b 100644
--- a/swad_course.c
+++ b/swad_course.c
@@ -36,6 +36,7 @@
 #include "swad_course.h"
 #include "swad_course_config.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_figure.h"
 #include "swad_figure_cache.h"
 #include "swad_form.h"
@@ -215,7 +216,7 @@ static void Crs_WriteListMyCoursesToSelectOne (void)
       /***** Get data of this institution *****/
       Hie.Cty.CtyCod = Str_ConvertStrCodToLongCod (row[0]);
       if (!Cty_GetDataOfCountryByCod (&Hie.Cty))
-	 Lay_WrongCountrExit ();
+	 Err_WrongCountrExit ();
 
       /***** Write link to country *****/
       Highlight = (Gbl.Hierarchy.Ins.InsCod <= 0 &&
@@ -249,7 +250,7 @@ static void Crs_WriteListMyCoursesToSelectOne (void)
 	 /***** Get data of this institution *****/
 	 Hie.Ins.InsCod = Str_ConvertStrCodToLongCod (row[0]);
 	 if (!Ins_GetDataOfInstitutionByCod (&Hie.Ins))
-	    Lay_WrongInstitExit ();
+	    Err_WrongInstitExit ();
 
 	 /***** Write link to institution *****/
 	 Highlight = (Gbl.Hierarchy.Ctr.CtrCod <= 0 &&
@@ -283,7 +284,7 @@ static void Crs_WriteListMyCoursesToSelectOne (void)
 	    /***** Get data of this center *****/
 	    Hie.Ctr.CtrCod = Str_ConvertStrCodToLongCod (row[0]);
 	    if (!Ctr_GetDataOfCenterByCod (&Hie.Ctr))
-	       Lay_WrongCenterExit ();
+	       Err_WrongCenterExit ();
 
 	    /***** Write link to center *****/
 	    Highlight = (Gbl.Hierarchy.Level == Hie_Lvl_CTR &&
@@ -317,7 +318,7 @@ static void Crs_WriteListMyCoursesToSelectOne (void)
 	       /***** Get data of this degree *****/
 	       Hie.Deg.DegCod = Str_ConvertStrCodToLongCod (row[0]);
 	       if (!Deg_GetDataOfDegreeByCod (&Hie.Deg))
-		  Lay_WrongDegreeExit ();
+		  Err_WrongDegreeExit ();
 
 	       /***** Write link to degree *****/
 	       Highlight = (Gbl.Hierarchy.Level == Hie_Lvl_DEG &&
@@ -351,7 +352,7 @@ static void Crs_WriteListMyCoursesToSelectOne (void)
 		  /***** Get data of this course *****/
 		  Hie.Crs.CrsCod = Str_ConvertStrCodToLongCod (row[0]);
 		  if (!Crs_GetDataOfCourseByCod (&Hie.Crs))
-		     Lay_WrongCourseExit ();
+		     Err_WrongCourseExit ();
 
 		  /***** Write link to course *****/
 		  Highlight = (Gbl.Hierarchy.Level == Hie_Lvl_CRS &&
@@ -711,7 +712,7 @@ void Crs_WriteSelectorOfCourse (void)
 
          /* Get course code (row[0]) */
          if ((CrsCod = Str_ConvertStrCodToLongCod (row[0])) < 0)
-            Lay_WrongCourseExit ();
+            Err_WrongCourseExit ();
 
          /* Write option */
 	 HTM_OPTION (HTM_Type_LONG,&CrsCod,
@@ -812,7 +813,7 @@ static void Crs_GetListCrssInCurrentDeg (Crs_WhatCourses_t WhatCourses)
       /***** Create list with courses in degree *****/
       if ((Gbl.Hierarchy.Crss.Lst = calloc (NumCrss,
 	                                    sizeof (*Gbl.Hierarchy.Ctys.Lst))) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
 
       /***** Get the courses in degree *****/
       for (NumCrs = 0;
@@ -1464,7 +1465,7 @@ static void Crs_PutFormToCreateCourse (void)
    else if (Gbl.Usrs.Me.Role.Max >= Rol_GST)
       Frm_BeginForm (ActReqCrs);
    else
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Begin box and table *****/
    Box_BoxTableBegin (NULL,Txt_New_course,
@@ -1772,7 +1773,7 @@ void Crs_RemoveCourse (void)
         }
      }
    else
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
   }
 
 /*****************************************************************************/
@@ -1833,7 +1834,7 @@ static void Crs_GetDataOfCourseFromRow (struct Crs_Course *Crs,MYSQL_ROW row)
   {
    /***** Get course code (row[0]) *****/
    if ((Crs->CrsCod = Str_ConvertStrCodToLongCod (row[0])) < 0)
-      Lay_WrongCourseExit ();
+      Err_WrongCourseExit ();
 
    /***** Get code of degree (row[1]) *****/
    Crs->DegCod = Str_ConvertStrCodToLongCod (row[1]);
@@ -1846,7 +1847,7 @@ static void Crs_GetDataOfCourseFromRow (struct Crs_Course *Crs,MYSQL_ROW row)
 
    /***** Get course status (row[4]) *****/
    if (sscanf (row[4],"%u",&(Crs->Status)) != 1)
-      Lay_WrongStatusExit ();
+      Err_WrongStatusExit ();
 
    /***** Get requester user'code (row[5]) *****/
    Crs->RequesterUsrCod = Str_ConvertStrCodToLongCod (row[5]);
@@ -2128,7 +2129,7 @@ void Crs_ChangeInsCrsCod (void)
                           Crs_EditingCrs->ShrtName);
      }
    else
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
   }
 
 /*****************************************************************************/
@@ -2191,7 +2192,7 @@ void Crs_ChangeCrsYear (void)
 			  NewYear);
      }
    else
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
   }
 
 /*****************************************************************************/
@@ -2332,7 +2333,7 @@ void Crs_RenameCourse (struct Crs_Course *Crs,Cns_ShrtOrFullName_t ShrtOrFullNam
          Ale_CreateAlertYouCanNotLeaveFieldEmpty ();
      }
    else
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
   }
 
 /*****************************************************************************/
@@ -2397,7 +2398,7 @@ void Crs_ChangeCrsStatus (void)
 	                              (unsigned long) Crs_MAX_STATUS,
                                       (unsigned long) Crs_WRONG_STATUS);
    if (Status == Crs_WRONG_STATUS)
-      Lay_WrongStatusExit ();
+      Err_WrongStatusExit ();
    StatusTxt = Crs_GetStatusTxtFromStatusBits (Status);
    Status = Crs_GetStatusBitsFromStatusTxt (StatusTxt);	// New status
 
@@ -2619,7 +2620,7 @@ static long Crs_GetAndCheckParamOtherCrsCod (long MinCodAllowed)
 
    /***** Get and check parameter with code of course *****/
    if ((CrsCod = Par_GetParToLong ("OthCrsCod")) < MinCodAllowed)
-      Lay_WrongCourseExit ();
+      Err_WrongCourseExit ();
 
    return CrsCod;
   }
@@ -2647,12 +2648,12 @@ void Crs_GetAndWriteCrssOfAUsr (const struct UsrData *UsrDat,Rol_Role_t Role)
    if (Role == Rol_UNK)	// Role == Rol_UNK ==> any role
      {
       if (asprintf (&SubQuery,"%s","") < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
      }
    else
      {
       if (asprintf (&SubQuery," AND crs_users.Role=%u",(unsigned) Role) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
      }
    NumCrss = (unsigned)
    DB_QuerySELECT (&mysql_res,"can not get courses of a user",
@@ -2826,13 +2827,13 @@ static void Crs_WriteRowCrsData (unsigned NumCrs,MYSQL_ROW row,bool WriteColumnA
 
    /***** Get degree code (row[0]) *****/
    if ((Deg.DegCod = Str_ConvertStrCodToLongCod (row[0])) < 0)
-      Lay_WrongDegreeExit ();
+      Err_WrongDegreeExit ();
    if (!Deg_GetDataOfDegreeByCod (&Deg))
-      Lay_WrongDegreeExit ();
+      Err_WrongDegreeExit ();
 
    /***** Get course code (row[1]) *****/
    if ((CrsCod = Str_ConvertStrCodToLongCod (row[1])) < 0)
-      Lay_WrongCourseExit ();
+      Err_WrongCourseExit ();
 
    /***** Get number of teachers and students in this course *****/
    NumStds = Usr_GetNumUsrsInCrss (Hie_Lvl_CRS,CrsCod,1 << Rol_STD);
@@ -3024,7 +3025,7 @@ void Crs_RemoveOldCrss (void)
                                                    Crs_MAX_MONTHS_WITHOUT_ACCESS_TO_REMOVE_OLD_CRSS,
                                                    UINT_MAX);
    if (MonthsWithoutAccess == UINT_MAX)
-      Lay_ShowErrorAndExit ("Wrong number of months without clicks.");
+      Err_ShowErrorAndExit ("Wrong number of months without clicks.");
    SecondsWithoutAccess = (unsigned long) MonthsWithoutAccess * Dat_SECONDS_IN_ONE_MONTH;
 
    /***** Get old courses from database *****/
@@ -3071,11 +3072,11 @@ static void Crs_EditingCourseConstructor (void)
   {
    /***** Pointer must be NULL *****/
    if (Crs_EditingCrs != NULL)
-      Lay_WrongCourseExit ();
+      Err_WrongCourseExit ();
 
    /***** Allocate memory for course *****/
    if ((Crs_EditingCrs = malloc (sizeof (*Crs_EditingCrs))) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Reset course *****/
    Crs_EditingCrs->CrsCod      = -1L;
diff --git a/swad_course_config.c b/swad_course_config.c
index 3efdac57..789c94f3 100644
--- a/swad_course_config.c
+++ b/swad_course_config.c
@@ -33,6 +33,7 @@
 #include <string.h>		// For string functions
 
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_hierarchy.h"
@@ -445,7 +446,7 @@ static void CrsCfg_Indicators (void)
    if (asprintf (&Title,"%u %s %u",
 	         IndicatorsCrs.NumIndicators,
 	         Txt_of_PART_OF_A_TOTAL,Ind_NUM_INDICATORS) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    HTM_BUTTON_SUBMIT_Begin (Title,"BT_LINK DAT",NULL);
    HTM_TxtF ("%s&nbsp;",Title);
    Ico_PutIcon ((IndicatorsCrs.NumIndicators == Ind_NUM_INDICATORS) ? "check-circle.svg" :
diff --git a/swad_database.c b/swad_database.c
index 7ec55206..00e72ed6 100644
--- a/swad_database.c
+++ b/swad_database.c
@@ -36,6 +36,7 @@
 
 #include "swad_config.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_global.h"
 #include "swad_HTML.h"
 #include "swad_language.h"
@@ -3741,7 +3742,7 @@ static void DB_CreateTable (const char *Query)
 void DB_OpenDBConnection (void)
   {
    if (mysql_init (&Gbl.mysql) == NULL)
-      Lay_ShowErrorAndExit ("Can not init MySQL.");
+      Err_ShowErrorAndExit ("Can not init MySQL.");
 
    if (mysql_real_connect (&Gbl.mysql,Cfg_DATABASE_HOST,
 	                   Cfg_DATABASE_USER,Gbl.Config.DatabasePassword,
@@ -3774,13 +3775,13 @@ void DB_BuildQuery (char **Query,const char *fmt,...)
    int NumBytesPrinted;
 
    if (*Query != NULL)
-      Lay_ShowErrorAndExit ("Error building query.");
+      Err_ShowErrorAndExit ("Error building query.");
 
    va_start (ap,fmt);
    NumBytesPrinted = vasprintf (Query,fmt,ap);
    va_end (ap);
    if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
   }
 
 /*****************************************************************************/
@@ -3799,7 +3800,7 @@ unsigned long DB_QuerySELECT (MYSQL_RES **mysql_res,const char *MsgError,
    NumBytesPrinted = vasprintf (&Query,fmt,ap);
    va_end (ap);
    if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Do SELECT query *****/
    return DB_QuerySELECTusingQueryStr (Query,mysql_res,MsgError);
@@ -3823,7 +3824,7 @@ long DB_QuerySELECTCode (const char *MsgError,
    NumBytesPrinted = vasprintf (&Query,fmt,ap);
    va_end (ap);
    if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Do SELECT query *****/
    if (DB_QuerySELECTusingQueryStr (Query,&mysql_res,MsgError))	// Row found
@@ -3856,7 +3857,7 @@ unsigned DB_QuerySELECTUnsigned (const char *MsgError,
    NumBytesPrinted = vasprintf (&Query,fmt,ap);
    va_end (ap);
    if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Do SELECT query *****/
    if (DB_QuerySELECTusingQueryStr (Query,&mysql_res,MsgError))	// Row found
@@ -3891,7 +3892,7 @@ double DB_QuerySELECTDouble (const char *MsgError,
    NumBytesPrinted = vasprintf (&Query,fmt,ap);
    va_end (ap);
    if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Do SELECT query *****/
    if (DB_QuerySELECTusingQueryStr (Query,&mysql_res,MsgError))	// Row found
@@ -3926,7 +3927,7 @@ Rol_Role_t DB_QuerySELECTRole (const char *MsgError,
    NumBytesPrinted = vasprintf (&Query,fmt,ap);
    va_end (ap);
    if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Do SELECT query *****/
    if (DB_QuerySELECTusingQueryStr (Query,&mysql_res,MsgError))	// Row found
@@ -3963,7 +3964,7 @@ void DB_QuerySELECTString (char *Str,size_t StrSize,const char *MsgError,
    NumBytesPrinted = vasprintf (&Query,fmt,ap);
    va_end (ap);
    if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Do SELECT query *****/
    Str[0] = '\0';
@@ -3985,7 +3986,7 @@ void DB_QuerySELECTString (char *Str,size_t StrSize,const char *MsgError,
 	        "Too large string from database,"
                 " it exceed the maximum allowed size (%zu bytes).",
                 StrSize);
-      Lay_ShowErrorAndExit (ErrorTxt);
+      Err_ShowErrorAndExit (ErrorTxt);
      }
   }
 
@@ -4002,7 +4003,7 @@ static unsigned long DB_QuerySELECTusingQueryStr (char *Query,
    /***** Check that query string pointer
           does point to an allocated string *****/
    if (Query == NULL)
-      Lay_ShowErrorAndExit ("Wrong query string.");
+      Err_ShowErrorAndExit ("Wrong query string.");
 
    /***** Query database and free query string pointer *****/
    Result = mysql_query (&Gbl.mysql,Query);	// Returns 0 on success
@@ -4060,7 +4061,7 @@ unsigned long DB_QueryCOUNT (const char *MsgError,const char *fmt,...)
    NumBytesPrinted = vasprintf (&Query,fmt,ap);
    va_end (ap);
    if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Make query "SELECT COUNT(*) FROM..." *****/
    DB_QuerySELECTusingQueryStr (Query,&mysql_res,MsgError);
@@ -4068,7 +4069,7 @@ unsigned long DB_QueryCOUNT (const char *MsgError,const char *fmt,...)
    /***** Get number of rows *****/
    row = mysql_fetch_row (mysql_res);
    if (sscanf (row[0],"%lu",&NumRows) != 1)
-      Lay_ShowErrorAndExit ("Error when counting number of rows.");
+      Err_ShowErrorAndExit ("Error when counting number of rows.");
 
    /***** Free structure that stores the query result *****/
    DB_FreeMySQLResult (&mysql_res);
@@ -4091,7 +4092,7 @@ void DB_QueryINSERT (const char *MsgError,const char *fmt,...)
    NumBytesPrinted = vasprintf (&Query,fmt,ap);
    va_end (ap);
    if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Query database and free query string pointer *****/
    Result = mysql_query (&Gbl.mysql,Query);	// Returns 0 on success
@@ -4115,7 +4116,7 @@ long DB_QueryINSERTandReturnCode (const char *MsgError,const char *fmt,...)
    NumBytesPrinted = vasprintf (&Query,fmt,ap);
    va_end (ap);
    if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Query database and free query string pointer *****/
    Result = mysql_query (&Gbl.mysql,Query);	// Returns 0 on success
@@ -4142,7 +4143,7 @@ void DB_QueryREPLACE (const char *MsgError,const char *fmt,...)
    NumBytesPrinted = vasprintf (&Query,fmt,ap);
    va_end (ap);
    if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Query database and free query string pointer *****/
    Result = mysql_query (&Gbl.mysql,Query);	// Returns 0 on success
@@ -4166,7 +4167,7 @@ void DB_QueryUPDATE (const char *MsgError,const char *fmt,...)
    NumBytesPrinted = vasprintf (&Query,fmt,ap);
    va_end (ap);
    if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Query database and free query string pointer *****/
    Result = mysql_query (&Gbl.mysql,Query);	// Returns 0 on success
@@ -4190,7 +4191,7 @@ void DB_QueryDELETE (const char *MsgError,const char *fmt,...)
    NumBytesPrinted = vasprintf (&Query,fmt,ap);
    va_end (ap);
    if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Query database and free query string pointer *****/
    Result = mysql_query (&Gbl.mysql,Query);	// Returns 0 on success
@@ -4214,7 +4215,7 @@ void DB_Query (const char *MsgError,const char *fmt,...)
    NumBytesPrinted = vasprintf (&Query,fmt,ap);
    va_end (ap);
    if (NumBytesPrinted < 0)	// -1 if no memory or any other error
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Query database and free query string pointer *****/
    Result = mysql_query (&Gbl.mysql,Query);	// Returns 0 on success
@@ -4247,5 +4248,5 @@ void DB_ExitOnMySQLError (const char *Message)
 
    snprintf (BigErrorMsg,sizeof (BigErrorMsg),"Database error: %s (%s).",
              Message,mysql_error (&Gbl.mysql));
-   Lay_ShowErrorAndExit (BigErrorMsg);
+   Err_ShowErrorAndExit (BigErrorMsg);
   }
diff --git a/swad_date.c b/swad_date.c
index 8932857f..0589e42d 100644
--- a/swad_date.c
+++ b/swad_date.c
@@ -36,6 +36,7 @@
 #include "swad_config.h"
 #include "swad_database.h"
 #include "swad_date.h"
+#include "swad_error.h"
 #include "swad_figure.h"
 #include "swad_form.h"
 #include "swad_global.h"
@@ -384,7 +385,7 @@ struct tm *Dat_GetLocalTimeFromClock (const time_t *timep)
    struct tm *tm_ptr;
 
    if ((tm_ptr = localtime (timep)) == NULL)
-      Lay_ShowErrorAndExit ("Can not get local time from clock.");
+      Err_ShowErrorAndExit ("Can not get local time from clock.");
 
    /***** Convert from sunday, monday, tuesday...
 	  to monday, tuesday, wednesday... *****/
@@ -716,9 +717,9 @@ void Dat_WriteFormClientLocalDateTimeFromTimeUTC (const char *Id,
 
    /***** Hidden field with UTC time (seconds since 1970) used to send time *****/
    if (asprintf (&IdTimeUTC,"%sTimeUTC",Id) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    if (asprintf (&ParamNameTimeUTC,"%sTimeUTC",ParamName) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    Par_PutHiddenParamLong (IdTimeUTC,ParamNameTimeUTC,(long) TimeUTC);
    free (ParamNameTimeUTC);
    free (IdTimeUTC);
diff --git a/swad_degree.c b/swad_degree.c
index a080a96a..0453c909 100644
--- a/swad_degree.c
+++ b/swad_degree.c
@@ -33,6 +33,7 @@
 #include "swad_database.h"
 #include "swad_degree.h"
 #include "swad_degree_config.h"
+#include "swad_error.h"
 #include "swad_figure.h"
 #include "swad_figure_cache.h"
 #include "swad_form.h"
@@ -296,7 +297,7 @@ void Deg_WriteSelectorOfDegree (void)
 
          /* Get degree code (row[0]) */
          if ((DegCod = Str_ConvertStrCodToLongCod (row[0])) < 0)
-            Lay_WrongDegreeExit ();
+            Err_WrongDegreeExit ();
 
          /* Write option */
 	 HTM_OPTION (HTM_Type_LONG,&DegCod,
@@ -604,7 +605,7 @@ static void Deg_PutFormToCreateDegree (void)
    else if (Gbl.Usrs.Me.Role.Max >= Rol_GST)
       Frm_BeginForm (ActReqDeg);
    else
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Begin box and table *****/
    Box_BoxTableBegin (NULL,Txt_New_degree,
@@ -904,7 +905,7 @@ static void Deg_ListOneDegreeForSeeing (struct Deg_Degree *Deg,unsigned NumDeg)
    /***** Get data of type of degree of this degree *****/
    DegTyp.DegTypCod = Deg->DegTypCod;
    if (!DT_GetDataOfDegreeTypeByCod (&DegTyp))
-      Lay_WrongDegTypExit ();
+      Err_WrongDegTypExit ();
 
    if (Deg->Status & Deg_STATUS_BIT_PENDING)
      {
@@ -1103,7 +1104,7 @@ void Deg_GetListAllDegsWithStds (struct ListDegrees *Degs)
      {
       /***** Create list with degrees *****/
       if ((Degs->Lst = calloc (Degs->Num,sizeof (*Degs->Lst))) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
 
       /***** Get the degrees *****/
       for (NumDeg = 0;
@@ -1155,7 +1156,7 @@ void Deg_GetListDegsInCurrentCtr (void)
       /***** Create list with degrees of this center *****/
       if ((Gbl.Hierarchy.Degs.Lst = calloc ((size_t) Gbl.Hierarchy.Degs.Num,
                                             sizeof (*Gbl.Hierarchy.Degs.Lst))) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
 
       /***** Get the degrees of this center *****/
       for (NumDeg = 0;
@@ -1339,7 +1340,7 @@ long Deg_GetAndCheckParamOtherDegCod (long MinCodAllowed)
 
    /***** Get and check parameter with code of degree *****/
    if ((DegCod = Par_GetParToLong ("OthDegCod")) < MinCodAllowed)
-      Lay_WrongDegreeExit ();
+      Err_WrongDegreeExit ();
 
    return DegCod;
   }
@@ -1404,7 +1405,7 @@ static void Deg_GetDataOfDegreeFromRow (struct Deg_Degree *Deg,MYSQL_ROW row)
   {
    /***** Get degree code (row[0]) *****/
    if ((Deg->DegCod = Str_ConvertStrCodToLongCod (row[0])) < 0)
-      Lay_WrongDegreeExit ();
+      Err_WrongDegreeExit ();
 
    /***** Get center code (row[1]) *****/
    Deg->CtrCod = Str_ConvertStrCodToLongCod (row[1]);
@@ -1414,7 +1415,7 @@ static void Deg_GetDataOfDegreeFromRow (struct Deg_Degree *Deg,MYSQL_ROW row)
 
    /* Get course status (row[3]) */
    if (sscanf (row[3],"%u",&(Deg->Status)) != 1)
-      Lay_WrongStatusExit ();
+      Err_WrongStatusExit ();
 
    /* Get requester user's code (row[4]) */
    Deg->RequesterUsrCod = Str_ConvertStrCodToLongCod (row[4]);
@@ -1512,7 +1513,7 @@ void Deg_RemoveDegreeCompletely (long DegCod)
      {
       /* Get next course */
       if ((CrsCod = DB_GetNextCode (mysql_res)) < 0)
-         Lay_WrongCourseExit ();
+         Err_WrongCourseExit ();
 
       /* Remove course */
       Crs_RemoveCourseCompletely (CrsCod);
@@ -1807,7 +1808,7 @@ void Deg_ChangeDegStatus (void)
 	                              (unsigned long) Deg_MAX_STATUS,
                                       (unsigned long) Deg_WRONG_STATUS);
    if (Status == Deg_WRONG_STATUS)
-      Lay_WrongStatusExit ();
+      Err_WrongStatusExit ();
    StatusTxt = Deg_GetStatusTxtFromStatusBits (Status);
    Status = Deg_GetStatusBitsFromStatusTxt (StatusTxt);	// New status
 
@@ -2197,11 +2198,11 @@ static void Deg_EditingDegreeConstructor (void)
   {
    /***** Pointer must be NULL *****/
    if (Deg_EditingDeg != NULL)
-      Lay_WrongDegreeExit ();
+      Err_WrongDegreeExit ();
 
    /***** Allocate memory for degree *****/
    if ((Deg_EditingDeg = malloc (sizeof (*Deg_EditingDeg))) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Reset degree *****/
    Deg_EditingDeg->DegCod          = -1L;
diff --git a/swad_degree_type.c b/swad_degree_type.c
index 89f82eb5..c145c1ff 100644
--- a/swad_degree_type.c
+++ b/swad_degree_type.c
@@ -37,6 +37,7 @@
 #include "swad_database.h"
 #include "swad_degree.h"
 #include "swad_degree_type.h"
+#include "swad_error.h"
 #include "swad_figure.h"
 #include "swad_form.h"
 #include "swad_global.h"
@@ -697,7 +698,7 @@ void DT_GetListDegreeTypes (Hie_Lvl_Level_t Scope,DT_Order_t Order)
 			 OrderBySubQuery[Order]);
 	 break;
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 break;
      }
 
@@ -707,7 +708,7 @@ void DT_GetListDegreeTypes (Hie_Lvl_Level_t Scope,DT_Order_t Order)
       /***** Create a list of degree types *****/
       if ((Gbl.DegTypes.Lst = calloc (Gbl.DegTypes.Num,
 			              sizeof (*Gbl.DegTypes.Lst))) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
 
       /***** Get degree types *****/
       for (NumTyp = 0;
@@ -719,7 +720,7 @@ void DT_GetListDegreeTypes (Hie_Lvl_Level_t Scope,DT_Order_t Order)
 
          /* Get degree type code (row[0]) */
          if ((Gbl.DegTypes.Lst[NumTyp].DegTypCod = Str_ConvertStrCodToLongCod (row[0])) <= 0)
-            Lay_WrongDegTypExit ();
+            Err_WrongDegTypExit ();
 
          /* Get degree type name (row[1]) */
          Str_Copy (Gbl.DegTypes.Lst[NumTyp].DegTypName,row[1],
@@ -727,7 +728,7 @@ void DT_GetListDegreeTypes (Hie_Lvl_Level_t Scope,DT_Order_t Order)
 
          /* Number of degrees of this type (row[2]) */
          if (sscanf (row[2],"%u",&Gbl.DegTypes.Lst[NumTyp].NumDegs) != 1)
-            Lay_ShowErrorAndExit ("Error when getting number of degrees of a type");
+            Err_ShowErrorAndExit ("Error when getting number of degrees of a type");
         }
      }
 
@@ -804,7 +805,7 @@ void DT_RemoveDegreeType (void)
 
    /***** Get data of the degree type from database *****/
    if (!DT_GetDataOfDegreeTypeByCod (DT_EditingDegTyp))
-      Lay_WrongDegTypExit ();
+      Err_WrongDegTypExit ();
 
    /***** Check if this degree type has degrees *****/
    if (DT_EditingDegTyp->NumDegs)	// Degree type has degrees => don't remove
@@ -842,7 +843,7 @@ long DT_GetAndCheckParamOtherDegTypCod (long MinCodAllowed)
 
    /***** Get and check parameter with code of degree type *****/
    if ((DegTypCod = Par_GetParToLong ("OthDegTypCod")) < MinCodAllowed)
-      Lay_WrongDegTypExit ();
+      Err_WrongDegTypExit ();
 
    return DegTypCod;
   }
@@ -921,7 +922,7 @@ static void DT_RemoveDegreeTypeCompletely (long DegTypCod)
      {
       /* Get next degree */
       if ((DegCod = DB_GetNextCode (mysql_res)) < 0)
-         Lay_WrongDegreeExit ();
+         Err_WrongDegreeExit ();
 
       /* Remove degree */
       Deg_RemoveDegreeCompletely (DegCod);
@@ -960,7 +961,7 @@ void DT_RenameDegreeType (void)
 
    /***** Get from the database the old name of the degree type *****/
    if (!DT_GetDataOfDegreeTypeByCod (DT_EditingDegTyp))
-      Lay_WrongDegTypExit ();
+      Err_WrongDegTypExit ();
 
    /***** Check if new name is empty *****/
    if (NewNameDegTyp[0])
@@ -1045,11 +1046,11 @@ static void DT_EditingDegreeTypeConstructor (void)
   {
    /***** Pointer must be NULL *****/
    if (DT_EditingDegTyp != NULL)
-      Lay_WrongDegTypExit ();
+      Err_WrongDegTypExit ();
 
    /***** Allocate memory for degree type *****/
    if ((DT_EditingDegTyp = malloc (sizeof (*DT_EditingDegTyp))) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Reset degree type *****/
    DT_EditingDegTyp->DegTypCod     = -1L;
diff --git a/swad_department.c b/swad_department.c
index 128fd1e1..fc9ab825 100644
--- a/swad_department.c
+++ b/swad_department.c
@@ -34,6 +34,7 @@
 #include "swad_constant.h"
 #include "swad_database.h"
 #include "swad_department.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_HTML.h"
@@ -377,7 +378,7 @@ static void Dpt_GetListDepartments (struct Dpt_Departments *Departments,long Ins
 	 /***** Create list with courses in degree *****/
 	 if ((Departments->Lst = calloc (Departments->Num,
 	                                 sizeof (*Departments->Lst))) == NULL)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Get the departments *****/
 	 for (NumDpt = 0;
@@ -391,11 +392,11 @@ static void Dpt_GetListDepartments (struct Dpt_Departments *Departments,long Ins
 
 	    /* Get department code (row[0]) */
 	    if ((Dpt->DptCod = Str_ConvertStrCodToLongCod (row[0])) <= 0)
-	       Lay_WrongDepartmentExit ();
+	       Err_WrongDepartmentExit ();
 
 	    /* Get institution code (row[1]) */
 	    if ((Dpt->InsCod = Str_ConvertStrCodToLongCod (row[1])) <= 0)
-	       Lay_WrongInstitExit ();
+	       Err_WrongInstitExit ();
 
 	    /* Get short name (row[2]), full name (row[3])
 	       and URL (row[4]) of the department  */
@@ -644,7 +645,7 @@ long Dpt_GetAndCheckParamDptCod (long MinCodAllowed)
 
    /***** Get and check parameter with code of department *****/
    if ((DptCod = Par_GetParToLong (Dpt_PARAM_DPT_COD_NAME)) < MinCodAllowed)
-      Lay_WrongDepartmentExit ();
+      Err_WrongDepartmentExit ();
 
    return DptCod;
   }
@@ -1206,11 +1207,11 @@ static void Dpt_EditingDepartmentConstructor (void)
   {
    /***** Pointer must be NULL *****/
    if (Dpt_EditingDpt != NULL)
-      Lay_WrongDepartmentExit ();
+      Err_WrongDepartmentExit ();
 
    /***** Allocate memory for department *****/
    if ((Dpt_EditingDpt = malloc (sizeof (*Dpt_EditingDpt))) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Reset department *****/
    Dpt_EditingDpt->DptCod      = -1L;
diff --git a/swad_duplicate.c b/swad_duplicate.c
index a2b8ed71..dc502717 100644
--- a/swad_duplicate.c
+++ b/swad_duplicate.c
@@ -30,6 +30,7 @@
 #include "swad_database.h"
 #include "swad_duplicate.h"
 #include "swad_enrolment.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_HTML.h"
@@ -204,7 +205,7 @@ void Dup_ListDuplicateUsrs (void)
 
             /* Write number of informants (row[1]) if greater than 1 */
 	    if (sscanf (row[1],"%u",&NumInformants) != 1)
-	       Lay_ShowErrorAndExit ("Wrong number of informants.");
+	       Err_ShowErrorAndExit ("Wrong number of informants.");
             if (NumInformants > 1)
               {
                HTM_TxtColonNBSP (Txt_Informants);
diff --git a/swad_enrolment.c b/swad_enrolment.c
index 657c2fcd..70cc3705 100644
--- a/swad_enrolment.c
+++ b/swad_enrolment.c
@@ -37,6 +37,7 @@
 #include "swad_database.h"
 #include "swad_duplicate.h"
 #include "swad_enrolment.h"
+#include "swad_error.h"
 #include "swad_exam_print.h"
 #include "swad_form.h"
 #include "swad_global.h"
@@ -243,7 +244,7 @@ void Enr_ModifyRoleInCurrentCrs (struct UsrData *UsrDat,Rol_Role_t NewRole)
       case Rol_TCH:
 	 break;
       default:
-	 Lay_WrongRoleExit ();
+	 Err_WrongRoleExit ();
      }
 
    /***** Update the role of a user in a course *****/
@@ -289,7 +290,7 @@ void Enr_RegisterUsrInCurrentCrs (struct UsrData *UsrDat,Rol_Role_t NewRole,
       case Rol_TCH:
 	 break;
       default:
-         Lay_WrongRoleExit ();
+         Err_WrongRoleExit ();
      }
 
    /***** Register user in current course in database *****/
@@ -363,7 +364,7 @@ static void Enr_NotifyAfterEnrolment (struct UsrData *UsrDat,Rol_Role_t NewRole)
 	 break;
       default:
 	 NotifyEvent = Ntf_EVENT_UNKNOWN;
-         Lay_WrongRoleExit ();
+         Err_WrongRoleExit ();
      }
 
    /***** Remove possible enrolment request ******/
@@ -453,7 +454,7 @@ void Enr_ReqAcceptRegisterInCrs (void)
 	 Frm_BeginForm (ActAccEnrTch);
 	 break;
       default:
-	 Lay_WrongRoleExit ();
+	 Err_WrongRoleExit ();
      }
    Btn_PutCreateButtonInline (Txt_Confirm_my_enrolment);
    Frm_EndForm ();
@@ -471,7 +472,7 @@ void Enr_ReqAcceptRegisterInCrs (void)
 	 Frm_BeginForm (ActRemMe_Tch);
 	 break;
       default:
-	 Lay_WrongRoleExit ();
+	 Err_WrongRoleExit ();
      }
    Btn_PutRemoveButtonInline (Txt_Remove_me_from_this_course);
    Frm_EndForm ();
@@ -493,7 +494,7 @@ void Enr_ReqAcceptRegisterInCrs (void)
 	 break;
       default:
 	 NotifyEvent = Ntf_EVENT_UNKNOWN;
-	 Lay_WrongRoleExit ();
+	 Err_WrongRoleExit ();
 	 break;
      }
    Ntf_MarkNotifAsSeen (NotifyEvent,-1L,Gbl.Hierarchy.Crs.CrsCod,
@@ -560,7 +561,7 @@ void Enr_UpdateUsrData (struct UsrData *UsrDat)
 
    /***** Check if user's code is initialized *****/
    if (UsrDat->UsrCod <= 0)
-      Lay_ShowErrorAndExit ("Can not update user's data. Wrong user's code.");
+      Err_ShowErrorAndExit ("Can not update user's data. Wrong user's code.");
 
    /***** Filter some user's data before updating */
    Enr_FilterUsrDat (UsrDat);
@@ -672,7 +673,7 @@ static void Enr_ReqAdminUsrs (Rol_Role_t Role)
 	    Enr_ReqAnotherUsrIDToRegisterRemove (Role);
 	 break;
       default:
-	 Lay_NoPermissionExit ();
+	 Err_NoPermissionExit ();
 	 break;
      }
   }
@@ -726,7 +727,7 @@ static void Enr_ShowFormRegRemSeveralUsrs (Rol_Role_t Role)
 	 default:
 	    NextAction = ActUnk;
 	    Title = NULL;
-	    Lay_WrongRoleExit ();
+	    Err_WrongRoleExit ();
 	    break;
 	}
 
@@ -751,7 +752,7 @@ static void Enr_ShowFormRegRemSeveralUsrs (Rol_Role_t Role)
       default:
 	 NextAction = ActUnk;
 	 Title = NULL;
-	 Lay_WrongRoleExit ();
+	 Err_WrongRoleExit ();
 	 break;
      }
    Frm_BeginForm (NextAction);
@@ -888,7 +889,7 @@ void Enr_RemoveOldUsrs (void)
                                                    Usr_MAX_MONTHS_WITHOUT_ACCESS_TO_REMOVE_OLD_USRS,
                                                    (unsigned long) UINT_MAX);
    if (MonthsWithoutAccess == UINT_MAX)
-      Lay_ShowErrorAndExit ("Wrong number of months.");
+      Err_ShowErrorAndExit ("Wrong number of months.");
    SecondsWithoutAccess = (time_t) MonthsWithoutAccess * Dat_SECONDS_IN_ONE_MONTH;
 
    /***** Get old users from database *****/
@@ -1106,16 +1107,16 @@ static void Enr_ReceiveFormUsrsCrs (Rol_Role_t Role)
       case Rol_STD:
 	 if (Gbl.Usrs.Me.Role.Logged < Rol_TCH)		// Can I register/remove students?
 	    // No, I can not
-	    Lay_NoPermissionExit ();
+	    Err_NoPermissionExit ();
 	 break;
       case Rol_NET:
       case Rol_TCH:
 	 if (Gbl.Usrs.Me.Role.Logged < Rol_DEG_ADM)	// Can I register/remove teachers?
 	    // No, I can not
-	    Lay_NoPermissionExit ();
+	    Err_NoPermissionExit ();
 	 break;
       default:
-	 Lay_WrongRoleExit ();
+	 Err_WrongRoleExit ();
 	 break;
      }
 
@@ -1169,10 +1170,10 @@ static void Enr_ReceiveFormUsrsCrs (Rol_Role_t Role)
 	    WhatToDo.RegisterUsrs = false;
 	   }
 	 else
-	    Lay_NoPermissionExit ();
+	    Err_NoPermissionExit ();
 	 break;
       default:
-	 Lay_ShowErrorAndExit ("Wrong registering / removing specification.");
+	 Err_ShowErrorAndExit ("Wrong registering / removing specification.");
 	 break;
      }
 
@@ -1206,7 +1207,7 @@ static void Enr_ReceiveFormUsrsCrs (Rol_Role_t Role)
 
    /***** Get list of users' IDs *****/
    if ((ListUsrsIDs = malloc (ID_MAX_BYTES_LIST_USRS_IDS + 1)) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    Par_GetParToText ("UsrsIDs",ListUsrsIDs,ID_MAX_BYTES_LIST_USRS_IDS);
 
    /***** Initialize structure with user's data *****/
@@ -1810,7 +1811,7 @@ static void Enr_RegisterUsr (struct UsrData *UsrDat,Rol_Role_t RegRemRole,
    /***** Check if I can register this user *****/
    if (Gbl.Usrs.Me.Role.Logged == Rol_TCH &&
        RegRemRole != Rol_STD)
-      Lay_ShowErrorAndExit ("A teacher only can register several users as students.");
+      Err_ShowErrorAndExit ("A teacher only can register several users as students.");
 
    /***** Check if the record of the user exists and get the type of user *****/
    if (UsrDat->UsrCod > 0)	// User exists in database
@@ -1982,7 +1983,7 @@ void Enr_ReqSignUpInCrs (void)
       /***** Show form to modify only the user's role or the user's data *****/
       Rec_ShowFormSignUpInCrsWithMySharedRecord ();
    else
-      Lay_ShowErrorAndExit ("You must be logged to sign up in a course.");        // This never should happen
+      Err_ShowErrorAndExit ("You must be logged to sign up in a course.");        // This never should happen
   }
 
 /*****************************************************************************/
@@ -2016,7 +2017,7 @@ void Enr_SignUpInCrs (void)
       if (!(RoleFromForm == Rol_STD ||
 	    RoleFromForm == Rol_NET ||
             RoleFromForm == Rol_TCH))
-         Lay_WrongRoleExit ();
+         Err_WrongRoleExit ();
 
       /***** Try to get and old request of the same user in the same course from database *****/
       ReqCod = DB_QuerySELECTCode ("can not get enrolment request",
@@ -2115,7 +2116,7 @@ void Enr_GetNotifEnrolmentRequest (char SummaryStr[Ntf_MAX_BYTES_SUMMARY + 1],
 	 if (asprintf (ContentStr,
 		       "%s",	// TODO: Write more info in this content
 		       Txt_ROLES_SINGUL_Abc[DesiredRole][UsrDat.Sex]) < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
       /* Free memory used for user's data */
       Usr_UsrDataDestructor (&UsrDat);
@@ -2179,7 +2180,7 @@ void Enr_AskIfRejectSignUp (void)
 				     Btn_REMOVE_BUTTON,Txt_Reject);
            }
          else
-            Lay_WrongRoleExit ();
+            Err_WrongRoleExit ();
         }
      }
    else
@@ -2247,7 +2248,7 @@ void Enr_ShowEnrolmentRequests (void)
 			                      (1 << Rol_TCH));
 	 break;
       default:
-	 Lay_NoPermissionExit ();
+	 Err_NoPermissionExit ();
 	 break;
      }
   }
@@ -2465,7 +2466,7 @@ static void Enr_ShowEnrolmentRequestsGivenRoles (unsigned RolesSelected)
 			       RolesSelected);
                break;
             default:
-               Lay_NoPermissionExit ();
+               Err_NoPermissionExit ();
                break;
            }
          break;
@@ -2617,7 +2618,7 @@ static void Enr_ShowEnrolmentRequestsGivenRoles (unsigned RolesSelected)
 			       RolesSelected);
                break;
             default:
-               Lay_NoPermissionExit ();
+               Err_NoPermissionExit ();
                break;
            }
          break;
@@ -2731,7 +2732,7 @@ static void Enr_ShowEnrolmentRequestsGivenRoles (unsigned RolesSelected)
 			       RolesSelected);
                break;
             default:
-               Lay_NoPermissionExit ();
+               Err_NoPermissionExit ();
                break;
            }
          break;
@@ -2813,7 +2814,7 @@ static void Enr_ShowEnrolmentRequestsGivenRoles (unsigned RolesSelected)
 			       RolesSelected);
                break;
             default:
-               Lay_NoPermissionExit ();
+               Err_NoPermissionExit ();
                break;
            }
          break;
@@ -2866,7 +2867,7 @@ static void Enr_ShowEnrolmentRequestsGivenRoles (unsigned RolesSelected)
 			       RolesSelected);
                break;
             default:
-               Lay_NoPermissionExit ();
+               Err_NoPermissionExit ();
                break;
            }
          break;
@@ -2894,12 +2895,12 @@ static void Enr_ShowEnrolmentRequestsGivenRoles (unsigned RolesSelected)
 			       RolesSelected);
                break;
             default:
-               Lay_NoPermissionExit ();
+               Err_NoPermissionExit ();
                break;
            }
          break;
       default:
-         Lay_WrongScopeExit ();
+         Err_WrongScopeExit ();
          break;
      }
 
@@ -3026,7 +3027,7 @@ static void Enr_ShowEnrolmentRequestsGivenRoles (unsigned RolesSelected)
 			   break;
 			default:
 			   NextAction = ActUnk;
-			   Lay_WrongRoleExit ();
+			   Err_WrongRoleExit ();
 			   break;
 		       }
 		     Frm_BeginForm (NextAction);
@@ -3172,7 +3173,7 @@ void Enr_PutLinkToAdminSeveralUsrs (Rol_Role_t Role)
       default:
 	 NextAction = ActUnk;
 	 TitleText = NULL;
-	 Lay_WrongRoleExit ();
+	 Err_WrongRoleExit ();
      }
    Lay_PutContextualLinkIconText (NextAction,NULL,
                                   NULL,NULL,
@@ -3252,7 +3253,7 @@ static void Enr_ReqAnotherUsrIDToRegisterRemove (Rol_Role_t Role)
 	 break;
       default:
 	 NextAction = ActUnk;
-         Lay_WrongRoleExit ();
+         Err_WrongRoleExit ();
 	 break;
      }
    Enr_WriteFormToReqAnotherUsrID (NextAction,NULL);
@@ -3890,7 +3891,7 @@ void Enr_CreateNewUsr1 (void)
 	    Gbl.Action.Act = ActCreTch;
 	    break;
 	 default:
-	    Lay_WrongRoleExit ();
+	    Err_WrongRoleExit ();
 	    break;
         }
       Tab_SetCurrentTab ();
@@ -4021,7 +4022,7 @@ void Enr_ModifyUsr1 (void)
 			Gbl.Action.Act = ActUpdTch;
 			break;
 		     default:
-			Lay_WrongRoleExit ();
+			Err_WrongRoleExit ();
 			break;
 		    }
 		  Tab_SetCurrentTab ();
@@ -4186,7 +4187,7 @@ static void Enr_AskIfRemoveUsrFromCrs (struct UsrData *UsrDat)
 	    break;
 	 default:
 	    NextAction = ActUnk;
-	    Lay_WrongRoleExit ();
+	    Err_WrongRoleExit ();
 	    break;
         }
       Frm_BeginForm (NextAction);
diff --git a/swad_error.c b/swad_error.c
new file mode 100644
index 00000000..5a08c03e
--- /dev/null
+++ b/swad_error.c
@@ -0,0 +1,600 @@
+// swad_layout.c: page layout
+
+/*
+    SWAD (Shared Workspace At a Distance),
+    is a web platform developed at the University of Granada (Spain),
+    and used to support university teaching.
+
+    This file is part of SWAD core.
+    Copyright (C) 1999-2021 Antonio Cañas Vargas
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as
+    published by the Free Software Foundation, either version 3 of the
+    License, or (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+/*****************************************************************************/
+/********************************* Headers ***********************************/
+/*****************************************************************************/
+
+#include "swad_database.h"
+#include "swad_error.h"
+#include "swad_global.h"
+#include "swad_layout.h"
+#include "swad_log.h"
+#include "swad_statistic.h"
+
+/*****************************************************************************/
+/************** External global variables from others modules ****************/
+/*****************************************************************************/
+
+extern struct Globals Gbl;
+
+/*****************************************************************************/
+/****************************** Public constants *****************************/
+/*****************************************************************************/
+
+/*****************************************************************************/
+/***************************** Private constants *****************************/
+/*****************************************************************************/
+
+/*****************************************************************************/
+/******************************* Private types *******************************/
+/*****************************************************************************/
+
+/*****************************************************************************/
+/***************************** Private prototypes ****************************/
+/*****************************************************************************/
+
+/*****************************************************************************/
+/********** Write error message and exit when not enough memory **************/
+/*****************************************************************************/
+
+void Err_NotEnoughMemoryExit (void)
+  {
+   Err_ShowErrorAndExit ("Not enough memory.");
+  }
+
+/*****************************************************************************/
+/************* Write error message and exit when wrong action ****************/
+/*****************************************************************************/
+
+void Err_WrongActionExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong action.");
+  }
+
+/*****************************************************************************/
+/************* Write error message and exit when wrong scope *****************/
+/*****************************************************************************/
+
+void Err_WrongScopeExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong scope.");
+  }
+
+/*****************************************************************************/
+/********* Write error message and exit                              *********/
+/********* when wrong country, institution, center, degree or course *********/
+/*****************************************************************************/
+
+void Err_WrongCountrExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong country.");
+  }
+
+void Err_WrongInstitExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong institution.");
+  }
+
+void Err_WrongCenterExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong center.");
+  }
+
+void Err_WrongDegTypExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong degree type.");
+  }
+
+void Err_WrongDegreeExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong degree.");
+  }
+
+void Err_WrongCourseExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong course.");
+  }
+
+/*****************************************************************************/
+/*********** Write error message and exit when wrong department **************/
+/*****************************************************************************/
+
+void Err_WrongDepartmentExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong department.");
+  }
+
+/*****************************************************************************/
+/************** Write error message and exit when wrong place ****************/
+/*****************************************************************************/
+
+void Err_WrongPlaceExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong department.");
+  }
+
+/*****************************************************************************/
+/************* Write error message and exit when wrong order *****************/
+/*****************************************************************************/
+
+void Err_WrongOrderExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong order.");
+  }
+
+/*****************************************************************************/
+/************* Write error message and exit when wrong status ****************/
+/*****************************************************************************/
+
+void Err_WrongStatusExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong status.");
+  }
+
+/*****************************************************************************/
+/************* Write error message and exit when wrong date ****************/
+/*****************************************************************************/
+
+void Err_WrongDateExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong date.");
+  }
+
+/*****************************************************************************/
+/************** Write error message and exit when wrong plugin ***************/
+/*****************************************************************************/
+
+void Err_WrongPluginExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong plugin.");
+  }
+
+/*****************************************************************************/
+/********** Write error message and exit when wrong items list/item **********/
+/*****************************************************************************/
+
+void Err_WrongItemsListExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong items list.");
+  }
+
+void Err_WrongItemExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong item.");
+  }
+
+/*****************************************************************************/
+/********** Write error message and exit when wrong syllabus format **********/
+/*****************************************************************************/
+
+void Err_WrongSyllabusFormatExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong syllabus format.");
+  }
+
+/*****************************************************************************/
+/*********** Write error message and exit when wrong file browser ************/
+/*****************************************************************************/
+
+void Err_WrongFileBrowserExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong file browser.");
+  }
+
+/*****************************************************************************/
+/*********** Write error message and exit when wrong copy source *************/
+/*****************************************************************************/
+
+void Err_WrongCopySrcExit (void)
+  {
+   Err_ShowErrorAndExit ("The copy source does not exist.");
+  }
+
+/*****************************************************************************/
+/********** Write error message and exit when wrong number of rows ***********/
+/*****************************************************************************/
+
+void Err_WrongNumberOfRowsExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong number of rows.");
+  }
+
+/*****************************************************************************/
+/********* Write error message and exit when wrong group type/group **********/
+/*****************************************************************************/
+
+void Err_WrongGrpTypExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong group type.");
+  }
+
+void Err_WrongGroupExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong group.");
+  }
+
+/*****************************************************************************/
+/************* Write error message and exit when wrong order *****************/
+/*****************************************************************************/
+
+void Err_WrongTypeOfViewExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong type of view.");
+  }
+
+/*****************************************************************************/
+/*********** Write error message and exit when wrong banner/link *************/
+/*****************************************************************************/
+
+void Err_WrongBannerExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong banner.");
+  }
+
+void Err_WrongLinkExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong link.");
+  }
+
+/*****************************************************************************/
+/************* Write error message and exit when wrong holiday ***************/
+/*****************************************************************************/
+
+void Err_WrongHolidayExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong holiday.");
+  }
+
+/*****************************************************************************/
+/********** Write error message and exit when wrong building/room ************/
+/*****************************************************************************/
+
+void Err_WrongBuildingExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong building.");
+  }
+
+void Err_WrongRoomExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong room.");
+  }
+
+/*****************************************************************************/
+/*********** Write error message and exit when wrong record field ************/
+/*****************************************************************************/
+
+void Err_WrongRecordFieldExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong record field.");
+  }
+
+/*****************************************************************************/
+/*********** Write error message and exit when wrong assignment **************/
+/*****************************************************************************/
+
+void Err_WrongAssignmentExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong assignment.");
+  }
+
+/*****************************************************************************/
+/************* Write error message and exit when wrong project ***************/
+/*****************************************************************************/
+
+void Err_WrongProjectExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong project.");
+  }
+
+/*****************************************************************************/
+/********** Write error message and exit when wrong call for exam ************/
+/*****************************************************************************/
+
+void Err_WrongCallForExamExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong call for exam.");
+  }
+
+/*****************************************************************************/
+/************** Write error message and exit when wrong tag *****************/
+/*****************************************************************************/
+
+void Err_WrongTagExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong tag.");
+  }
+
+/*****************************************************************************/
+/************** Write error message and exit when wrong test *****************/
+/*****************************************************************************/
+
+void Err_WrongTestExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong test.");
+  }
+
+/*****************************************************************************/
+/************** Write error message and exit when wrong exam *****************/
+/*****************************************************************************/
+
+void Err_WrongExamExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong exam.");
+  }
+
+/*****************************************************************************/
+/********* Write error message and exit when wrong set of questions **********/
+/*****************************************************************************/
+
+void Err_WrongSetExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong set of questions.");
+  }
+
+/*****************************************************************************/
+/************* Write error message and exit when wrong question **************/
+/*****************************************************************************/
+
+void Err_WrongQuestionExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong question.");
+  }
+
+void Err_WrongQuestionIndexExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong question index.");
+  }
+
+/*****************************************************************************/
+/************** Write error message and exit when wrong answer ***************/
+/*****************************************************************************/
+
+void Err_WrongAnswerExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong answer.");
+  }
+
+void Err_WrongAnswerIndexExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong answer index.");
+  }
+
+/*****************************************************************************/
+/*********** Write error message and exit when wrong exam session ************/
+/*****************************************************************************/
+
+void Err_WrongExamSessionExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong exam session.");
+  }
+
+/*****************************************************************************/
+/************ Write error message and exit when wrong game/match *************/
+/*****************************************************************************/
+
+void Err_WrongGameExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong game.");
+  }
+
+void Err_WrongMatchExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong match.");
+  }
+
+/*****************************************************************************/
+/************** Write error message and exit when wrong survey ***************/
+/*****************************************************************************/
+
+void Err_WrongSurveyExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong survey.");
+  }
+
+/*****************************************************************************/
+/*** Write error message and exit when wrong parameter "who" (which users) ***/
+/*****************************************************************************/
+
+void Err_WrongWhoExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong parameter who.");
+  }
+
+/*****************************************************************************/
+/**************** Write error message and exit when wrong event **************/
+/*****************************************************************************/
+
+void Err_WrongEventExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong event.");
+  }
+
+/*****************************************************************************/
+/*********** Write error message and exit when wrong announcement ************/
+/*****************************************************************************/
+
+void Err_WrongAnnouncementExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong announcement.");
+  }
+
+/*****************************************************************************/
+/************** Write error message and exit when wrong notice ***************/
+/*****************************************************************************/
+
+void Err_WrongNoticeExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong notice.");
+  }
+
+/*****************************************************************************/
+/************ Write error message and exit when wrong forum/post *************/
+/*****************************************************************************/
+
+void Err_WrongForumExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong forum.");
+  }
+
+void Err_WrongPostExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong post.");
+  }
+
+/*****************************************************************************/
+/************** Write error message and exit when wrong message **************/
+/*****************************************************************************/
+
+void Err_WrongMessageExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong message.");
+  }
+
+/*****************************************************************************/
+/************ Write error message and exit when wrong mail domain ************/
+/*****************************************************************************/
+
+void Err_WrongMailDomainExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong mail domain.");
+  }
+
+/*****************************************************************************/
+/************* Show error message about wrong role and exit ******************/
+/*****************************************************************************/
+
+void Err_WrongRoleExit (void)
+  {
+   Err_ShowErrorAndExit ("Wrong role.");
+  }
+
+/*****************************************************************************/
+/************ Write error message and exit when user does not exists *********/
+/*****************************************************************************/
+
+void Err_WrongUserExit (void)
+  {
+   extern const char *Txt_The_user_does_not_exist;
+
+   Err_ShowErrorAndExit (Txt_The_user_does_not_exist);
+  }
+
+/*****************************************************************************/
+/*** Write error message and exit when no permission to perform an action ****/
+/*****************************************************************************/
+
+void Err_NoPermissionExit (void)
+  {
+   extern const char *Txt_You_dont_have_permission_to_perform_this_action;
+
+   Err_ShowErrorAndExit (Txt_You_dont_have_permission_to_perform_this_action);
+  }
+
+/*****************************************************************************/
+/******* Write error message, close files, remove lock file, and exit ********/
+/*****************************************************************************/
+
+void Err_ShowErrorAndExit (const char *Txt)
+  {
+   /***** Unlock tables if locked *****/
+   if (Gbl.DB.LockedTables)
+     {
+      Gbl.DB.LockedTables = false;
+      mysql_query (&Gbl.mysql,"UNLOCK TABLES");
+     }
+
+   if (!Gbl.WebService.IsWebService)
+     {
+      /****** If start of page is not written yet, do it now ******/
+      if (!Gbl.Layout.HTMLStartWritten)
+	 Lay_WriteStartOfPage ();
+
+      /***** Write possible error message *****/
+      if (Txt)
+         Ale_ShowAlert (Ale_ERROR,Txt);
+
+      /***** Finish the page, except </body> and </html> *****/
+      Lay_WriteEndOfPage ();
+     }
+
+   /***** Free memory and close all the open files *****/
+   Gbl_Cleanup ();
+
+   /***** Page is generated (except </body> and </html>).
+          Compute time to generate page *****/
+   if (!Gbl.Action.IsAJAXAutoRefresh)
+      Gbl.TimeGenerationInMicroseconds = (long) Sta_ComputeTimeToGeneratePage ();
+
+   if (Gbl.WebService.IsWebService)		// Serving a plugin request
+     {
+      /***** Log access *****/
+      Gbl.TimeSendInMicroseconds = 0L;
+      Log_LogAccess (Txt);
+     }
+   else
+     {
+      /***** Send page.
+             The HTML output is now in Gbl.F.Out file ==>
+             ==> copy it to standard output *****/
+      rewind (Gbl.F.Out);
+      Fil_FastCopyOfOpenFiles (Gbl.F.Out,stdout);
+      Fil_CloseAndRemoveFileForHTMLOutput ();
+
+      if (!Gbl.Action.IsAJAXAutoRefresh)
+	{
+	 /***** Compute time to send page *****/
+	 Sta_ComputeTimeToSendPage ();
+
+	 /***** Log access *****/
+	 Log_LogAccess (Txt);
+
+	 /***** Update last data for next time *****/
+	 if (Gbl.Usrs.Me.Logged)
+	   {
+	    Usr_UpdateMyLastData ();
+	    Crs_UpdateCrsLast ();
+	   }
+
+	 /***** End the output *****/
+	 if (!Gbl.Layout.HTMLEndWritten)
+	   {
+	    // Here Gbl.F.Out is stdout
+	    if (Act_GetBrowserTab (Gbl.Action.Act) == Act_BRW_1ST_TAB)
+	       Lay_WriteAboutZone ();
+
+	    HTM_Txt ("</body>\n"
+		     "</html>\n");
+	    Gbl.Layout.HTMLEndWritten = true;
+	   }
+	}
+     }
+
+   /***** Close database connection *****/
+   DB_CloseDBConnection ();
+
+   /***** Exit *****/
+   if (Gbl.WebService.IsWebService)
+      API_Exit (Txt);
+   exit (0);
+  }
diff --git a/swad_error.h b/swad_error.h
new file mode 100644
index 00000000..74ffdaa0
--- /dev/null
+++ b/swad_error.h
@@ -0,0 +1,100 @@
+// swad_error.h: exit on error
+
+#ifndef _SWAD_ERR
+#define _SWAD_ERR
+/*
+    SWAD (Shared Workspace At a Distance in Spanish),
+    is a web platform developed at the University of Granada (Spain),
+    and used to support university teaching.
+
+    This file is part of SWAD core.
+    Copyright (C) 1999-2021 Antonio Cañas Vargas
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as
+    published by the Free Software Foundation, either version 3 of the
+    License, or (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+/*****************************************************************************/
+/********************************* Headers ***********************************/
+/*****************************************************************************/
+
+/*****************************************************************************/
+/****************************** Public constants *****************************/
+/*****************************************************************************/
+
+/*****************************************************************************/
+/********************************* Public types ******************************/
+/*****************************************************************************/
+
+/*****************************************************************************/
+/****************************** Public prototypes ****************************/
+/*****************************************************************************/
+
+void Err_NotEnoughMemoryExit (void);
+void Err_WrongActionExit (void);
+void Err_WrongScopeExit (void);
+void Err_WrongCountrExit (void);
+void Err_WrongInstitExit (void);
+void Err_WrongCenterExit (void);
+void Err_WrongDegTypExit (void);
+void Err_WrongDegreeExit (void);
+void Err_WrongCourseExit (void);
+void Err_WrongDepartmentExit (void);
+void Err_WrongPlaceExit (void);
+void Err_WrongOrderExit (void);
+void Err_WrongStatusExit (void);
+void Err_WrongDateExit (void);
+void Err_WrongPluginExit (void);
+void Err_WrongItemsListExit (void);
+void Err_WrongItemExit (void);
+void Err_WrongSyllabusFormatExit (void);
+void Err_WrongFileBrowserExit (void);
+void Err_WrongCopySrcExit (void);
+void Err_WrongNumberOfRowsExit (void);
+void Err_WrongGrpTypExit (void);
+void Err_WrongGroupExit (void);
+void Err_WrongTypeOfViewExit (void);
+void Err_WrongBannerExit (void);
+void Err_WrongLinkExit (void);
+void Err_WrongHolidayExit (void);
+void Err_WrongBuildingExit (void);
+void Err_WrongRoomExit (void);
+void Err_WrongRecordFieldExit (void);
+void Err_WrongAssignmentExit (void);
+void Err_WrongProjectExit (void);
+void Err_WrongCallForExamExit (void);
+void Err_WrongTagExit (void);
+void Err_WrongTestExit (void);
+void Err_WrongExamExit (void);
+void Err_WrongSetExit (void);
+void Err_WrongQuestionExit (void);
+void Err_WrongQuestionIndexExit (void);
+void Err_WrongAnswerExit (void);
+void Err_WrongAnswerIndexExit (void);
+void Err_WrongExamSessionExit (void);
+void Err_WrongGameExit (void);
+void Err_WrongMatchExit (void);
+void Err_WrongSurveyExit (void);
+void Err_WrongWhoExit (void);
+void Err_WrongEventExit (void);
+void Err_WrongAnnouncementExit (void);
+void Err_WrongNoticeExit (void);
+void Err_WrongForumExit (void);
+void Err_WrongPostExit (void);
+void Err_WrongMessageExit (void);
+void Err_WrongMailDomainExit (void);
+void Err_WrongRoleExit (void);
+void Err_WrongUserExit (void);
+void Err_NoPermissionExit (void);
+void Err_ShowErrorAndExit (const char *Txt);
+
+#endif
diff --git a/swad_exam.c b/swad_exam.c
index 90242ef0..10ad9d94 100644
--- a/swad_exam.c
+++ b/swad_exam.c
@@ -35,6 +35,7 @@
 #include <string.h>		// For string functions
 
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_exam.h"
 #include "swad_exam_print.h"
 #include "swad_exam_result.h"
@@ -425,7 +426,7 @@ void Exa_SeeOneExam (void)
    /***** Get parameters *****/
    Exa_GetParams (&Exams);
    if (Exams.ExaCod <= 0)
-      Lay_WrongExamExit ();
+      Err_WrongExamExit ();
    Exam.ExaCod = Exams.ExaCod;
 
    /***** Get exam data *****/
@@ -525,7 +526,7 @@ static void Exa_ShowOneExam (struct Exa_Exams *Exams,
 	StartEndTime++)
      {
       if (asprintf (&Id,"exa_date_%u_%u",(unsigned) StartEndTime,UniqueId) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       Color = Exam->NumOpenSess ? (Exam->Hidden ? "DATE_GREEN_LIGHT":
 						  "DATE_GREEN") :
 				  (Exam->Hidden ? "DATE_RED_LIGHT":
@@ -812,7 +813,7 @@ void Exa_GetListExams (struct Exa_Exams *Exams,Exa_Order_t SelectedOrder)
      {
       case Rol_STD:
          if (asprintf (&HiddenSubQuery," AND exa_exams.Hidden='N'") < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 	 break;
       case Rol_NET:
       case Rol_TCH:
@@ -821,10 +822,10 @@ void Exa_GetListExams (struct Exa_Exams *Exams,Exa_Order_t SelectedOrder)
       case Rol_INS_ADM:
       case Rol_SYS_ADM:
 	 if (asprintf (&HiddenSubQuery,"%s","") < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 	 break;
       default:
-	 Lay_WrongRoleExit ();
+	 Err_WrongRoleExit ();
 	 break;
      }
 
@@ -853,7 +854,7 @@ void Exa_GetListExams (struct Exa_Exams *Exams,Exa_Order_t SelectedOrder)
       /***** Create list of exams *****/
       if ((Exams->Lst = malloc ((size_t) Exams->Num *
                                 sizeof (*Exams->Lst))) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
 
       /***** Get the exams codes *****/
       for (NumExam = 0;
@@ -863,7 +864,7 @@ void Exa_GetListExams (struct Exa_Exams *Exams,Exa_Order_t SelectedOrder)
          /* Get next exam code (row[0]) */
          row = mysql_fetch_row (mysql_res);
          if ((Exams->Lst[NumExam].ExaCod = Str_ConvertStrCodToLongCod (row[0])) <= 0)
-            Lay_WrongExamExit ();
+            Err_WrongExamExit ();
         }
      }
 
@@ -888,7 +889,7 @@ void Exa_GetListSelectedExaCods (struct Exa_Exams *Exams)
    /***** Allocate memory for list of exams selected *****/
    MaxSizeListExaCodsSelected = Exams->Num * (Cns_MAX_DECIMAL_DIGITS_LONG + 1);
    if ((Exams->ExaCodsSelected = malloc (MaxSizeListExaCodsSelected + 1)) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Get parameter multiple with list of exams selected *****/
    Par_GetParMultiToText ("ExaCod",Exams->ExaCodsSelected,MaxSizeListExaCodsSelected);
@@ -1083,7 +1084,7 @@ void Exa_AskRemExam (void)
 
    /***** Check if I can edit exams *****/
    if (!Exa_CheckIfICanEditExams ())
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Reset exams context *****/
    Exa_ResetExams (&Exams);
@@ -1092,7 +1093,7 @@ void Exa_AskRemExam (void)
    /***** Get parameters *****/
    Exa_GetParams (&Exams);
    if (Exams.ExaCod <= 0)
-      Lay_WrongExamExit ();
+      Err_WrongExamExit ();
    Exam.ExaCod = Exams.ExaCod;
 
    /***** Get data of the exam from database *****/
@@ -1123,7 +1124,7 @@ void Exa_RemoveExam (void)
 
    /***** Check if I can edit exams *****/
    if (!Exa_CheckIfICanEditExams ())
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Reset exams context *****/
    Exa_ResetExams (&Exams);
@@ -1131,7 +1132,7 @@ void Exa_RemoveExam (void)
 
    /***** Get exam code *****/
    if ((Exam.ExaCod = Exa_GetParamExamCod ()) <= 0)
-      Lay_WrongExamExit ();
+      Err_WrongExamExit ();
 
    /***** Get data of the exam from database *****/
    Exa_GetDataOfExamByCod (&Exam);
@@ -1304,7 +1305,7 @@ void Exa_HideExam (void)
 
    /***** Check if I can edit exams *****/
    if (!Exa_CheckIfICanEditExams ())
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Reset exams context *****/
    Exa_ResetExams (&Exams);
@@ -1313,7 +1314,7 @@ void Exa_HideExam (void)
    /***** Get parameters *****/
    Exa_GetParams (&Exams);
    if (Exams.ExaCod <= 0)
-      Lay_WrongExamExit ();
+      Err_WrongExamExit ();
    Exam.ExaCod = Exams.ExaCod;
 
    /***** Get data of the exam from database *****/
@@ -1342,7 +1343,7 @@ void Exa_UnhideExam (void)
 
    /***** Check if I can edit exams *****/
    if (!Exa_CheckIfICanEditExams ())
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Reset exams context *****/
    Exa_ResetExams (&Exams);
@@ -1351,7 +1352,7 @@ void Exa_UnhideExam (void)
    /***** Get parameters *****/
    Exa_GetParams (&Exams);
    if (Exams.ExaCod <= 0)
-      Lay_WrongExamExit ();
+      Err_WrongExamExit ();
    Exam.ExaCod = Exams.ExaCod;
 
    /***** Get data of the exam from database *****/
@@ -1400,7 +1401,7 @@ void Exa_RequestCreatOrEditExam (void)
 
    /***** Check if I can edit exams *****/
    if (!Exa_CheckIfICanEditExams ())
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Reset exams context *****/
    Exa_ResetExams (&Exams);
@@ -1578,7 +1579,7 @@ void Exa_ReceiveFormExam (void)
 
    /***** Check if I can edit exams *****/
    if (!Exa_CheckIfICanEditExams ())
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Reset exams context *****/
    Exa_ResetExams (&Exams);
@@ -1746,7 +1747,7 @@ unsigned Exa_GetParamQstInd (void)
    long QstInd;
 
    if ((QstInd = Par_GetParToLong ("QstInd")) <= 0)
-      Lay_WrongQuestionIndexExit ();
+      Err_WrongQuestionIndexExit ();
 
    return (unsigned) QstInd;
   }
@@ -1768,7 +1769,7 @@ long Exa_GetQstCodFromQstInd (long ExaCod,unsigned QstInd)
 				ExaCod,
 				QstInd);
    if (QstCod <= 0)
-      Lay_WrongQuestionIndexExit ();
+      Err_WrongQuestionIndexExit ();
 
    return QstCod;
   }
@@ -1909,7 +1910,7 @@ unsigned Exa_GetNumCoursesWithExams (Hie_Lvl_Level_t Scope)
 			       " WHERE CrsCod=%ld",
 			       Gbl.Hierarchy.Crs.CrsCod);
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 return 0;	// Not reached
      }
   }
@@ -1979,7 +1980,7 @@ unsigned Exa_GetNumExams (Hie_Lvl_Level_t Scope)
 			       " WHERE CrsCod=%ld",
 			       Gbl.Hierarchy.Crs.CrsCod);
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 return 0;	// Not reached
      }
   }
@@ -2072,7 +2073,7 @@ double Exa_GetNumQstsPerCrsExam (Hie_Lvl_Level_t Scope)
 					      " GROUP BY exa_set_questions.ExaCod) AS NumQstsTable",
 				      Gbl.Hierarchy.Crs.CrsCod);
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 return 0.0;	// Not reached
      }
   }
@@ -2096,7 +2097,7 @@ void Exa_GetScoreRange (long ExaCod,double *MinScore,double *MaxScore)
 		  " GROUP BY tst_answers.QstCod",
 		  ExaCod);
    if (NumAnswers < 2)
-      Lay_ShowErrorAndExit ("Wrong number of answers.");
+      Err_ShowErrorAndExit ("Wrong number of answers.");
 
    /***** Set minimum and maximum scores *****/
    *MinScore = *MaxScore = 0.0;
diff --git a/swad_exam_log.c b/swad_exam_log.c
index 65acbf04..5a348e95 100644
--- a/swad_exam_log.c
+++ b/swad_exam_log.c
@@ -32,6 +32,7 @@
 
 #include "swad_action.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_exam_log.h"
 #include "swad_global.h"
 
@@ -231,7 +232,7 @@ static void ExaLog_LogUsrAgent (long LogCod,long PrnCod)
    else
       MaxBytes = 0;
    if ((UserAgentDB = malloc (MaxBytes + 1)) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    if (UserAgent)
      {
       Str_Copy (UserAgentDB,UserAgent,MaxBytes);
@@ -389,7 +390,7 @@ void ExaLog_ShowExamLog (const struct ExaPrn_Print *Print)
 	 /* Get session id (row[6]) */
 	 if (asprintf (&UserAgent,"%s",row[6] ? row[6] :
 						"=") < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Set color of row depending on action *****/
 	 if (UsrCouldAnswer)
@@ -422,7 +423,7 @@ void ExaLog_ShowExamLog (const struct ExaPrn_Print *Print)
 
 	 /* Write click time */
 	 if (asprintf (&Id,"click_date_%u",NumClick) < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 	 HTM_TD_Begin ("id=\"%s\" class=\"LT COLOR%u %s\"",Id,Gbl.RowEvenOdd,Class);
 	 Dat_WriteLocalDateHMSFromUTC (Id,ClickTimeUTC,
 				       Gbl.Prefs.DateFormat,Dat_SEPARATOR_COMMA,
diff --git a/swad_exam_print.c b/swad_exam_print.c
index 4dc49d41..e2dffced 100644
--- a/swad_exam_print.c
+++ b/swad_exam_print.c
@@ -33,6 +33,7 @@
 
 #include "swad_box.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_exam.h"
 #include "swad_exam_log.h"
 #include "swad_exam_print.h"
@@ -415,7 +416,7 @@ static void ExaPrn_GetQuestionsForNewPrintFromDB (struct ExaPrn_Print *Print,lon
 
    /***** Check *****/
    if (Print->NumQsts.All != NumQstInPrint)
-      Lay_ShowErrorAndExit ("Wrong number of questions.");
+      Err_ShowErrorAndExit ("Wrong number of questions.");
 
    /***** Free structure that stores the query result *****/
    DB_FreeMySQLResult (&mysql_res);
@@ -556,7 +557,7 @@ static void ExaPrn_GenerateChoiceIndexes (struct TstPrn_PrintedQuestion *Printed
       else
          ErrorInIndex = true;
       if (ErrorInIndex)
-         Lay_WrongAnswerIndexExit ();
+         Err_WrongAnswerIndexExit ();
 
       if (NumOpt == 0)
 	 snprintf (StrInd,sizeof (StrInd),"%u",Index);
@@ -635,16 +636,16 @@ void ExaPrn_GetPrintQuestionsFromDB (struct ExaPrn_Print *Print)
 
 	 /* Get question code (row[0]) */
 	 if ((Print->PrintedQuestions[NumQst].QstCod = Str_ConvertStrCodToLongCod (row[0])) < 0)
-	    Lay_WrongQuestionExit ();
+	    Err_WrongQuestionExit ();
 
 	 /* Get set code (row[1]) */
 	 if ((Print->PrintedQuestions[NumQst].SetCod = Str_ConvertStrCodToLongCod (row[1])) < 0)
-	    Lay_WrongSetExit ();
+	    Err_WrongSetExit ();
 
          /* Get score (row[2]) */
 	 Str_SetDecimalPointToUS ();	// To get the decimal point as a dot
          if (sscanf (row[2],"%lf",&Print->PrintedQuestions[NumQst].Score) != 1)
-            Lay_ShowErrorAndExit ("Wrong question score.");
+            Err_ShowErrorAndExit ("Wrong question score.");
          Str_SetDecimalPointToLocal ();	// Return to local system
 
 	 /* Get indexes for this question (row[3]) */
@@ -660,7 +661,7 @@ void ExaPrn_GetPrintQuestionsFromDB (struct ExaPrn_Print *Print)
    DB_FreeMySQLResult (&mysql_res);
 
    if (Print->NumQsts.All > ExaPrn_MAX_QUESTIONS_PER_EXAM_PRINT)
-      Lay_ShowErrorAndExit ("Too many questions.");
+      Err_ShowErrorAndExit ("Too many questions.");
   }
 
 /*****************************************************************************/
@@ -1066,22 +1067,22 @@ void ExaPrn_ReceivePrintAnswer (void)
    Print.UsrCod = Gbl.Usrs.Me.UsrDat.UsrCod;
    ExaPrn_GetDataOfPrintBySesCodAndUsrCod (&Print);
    if (Print.PrnCod <= 0)
-      Lay_WrongExamExit ();
+      Err_WrongExamExit ();
 
    /***** Get session data *****/
    Session.SesCod = Print.SesCod;
    ExaSes_GetDataOfSessionByCod (&Session);
    if (Session.SesCod <= 0)
-      Lay_WrongExamExit ();
+      Err_WrongExamExit ();
    Exams.SesCod = Session.SesCod;
 
    /***** Get exam data *****/
    Exam.ExaCod = Session.ExaCod;
    Exa_GetDataOfExamByCod (&Exam);
    if (Exam.ExaCod <= 0)
-      Lay_WrongExamExit ();
+      Err_WrongExamExit ();
    if (Exam.CrsCod != Gbl.Hierarchy.Crs.CrsCod)
-      Lay_WrongExamExit ();
+      Err_WrongExamExit ();
    Exams.ExaCod = Exam.ExaCod;
 
    /***** Get question index from form *****/
@@ -1153,7 +1154,7 @@ static unsigned ExaPrn_GetParamQstInd (void)
 
    NumQst = Par_GetParToLong ("NumQst");
    if (NumQst < 0)
-      Lay_ShowErrorAndExit ("Wrong number of question.");
+      Err_ShowErrorAndExit ("Wrong number of question.");
 
    return (unsigned) NumQst;
   }
@@ -1289,7 +1290,7 @@ static void ExaPrn_GetCorrectIntAnswerFromDB (struct Tst_Question *Question)
    /***** Get correct answer *****/
    row = mysql_fetch_row (mysql_res);
    if (sscanf (row[0],"%ld",&Question->Answer.Integer) != 1)
-      Lay_WrongAnswerExit ();
+      Err_WrongAnswerExit ();
 
    /***** Free structure that stores the query result *****/
    DB_FreeMySQLResult (&mysql_res);
@@ -1312,7 +1313,7 @@ static void ExaPrn_GetCorrectFltAnswerFromDB (struct Tst_Question *Question)
 
    /***** Check if number of rows is correct *****/
    if (Question->Answer.NumOptions != 2)
-      Lay_WrongAnswerExit ();
+      Err_WrongAnswerExit ();
 
    /***** Get float range *****/
    for (NumOpt = 0;
diff --git a/swad_exam_result.c b/swad_exam_result.c
index 333bda8c..5745cb16 100644
--- a/swad_exam_result.c
+++ b/swad_exam_result.c
@@ -35,6 +35,7 @@
 #include "swad_action.h"
 #include "swad_database.h"
 #include "swad_date.h"
+#include "swad_error.h"
 #include "swad_exam.h"
 #include "swad_exam_log.h"
 #include "swad_exam_print.h"
@@ -204,7 +205,7 @@ void ExaRes_ShowMyResultsInExa (void)
    /***** Get parameters *****/
    Exa_GetParams (&Exams);
    if (Exams.ExaCod <= 0)
-      Lay_WrongExamExit ();
+      Err_WrongExamExit ();
    Exam.ExaCod = Exams.ExaCod;
 
    /***** Get exam data from database *****/
@@ -256,10 +257,10 @@ void ExaRes_ShowMyResultsInSes (void)
    /***** Get parameters *****/
    Exa_GetParams (&Exams);
    if (Exams.ExaCod <= 0)
-      Lay_WrongExamExit ();
+      Err_WrongExamExit ();
    Exam.ExaCod = Exams.ExaCod;
    if ((Session.SesCod = ExaSes_GetParamSesCod ()) <= 0)
-      Lay_WrongExamSessionExit ();
+      Err_WrongExamSessionExit ();
    Exa_GetDataOfExamByCod (&Exam);
    Exams.ExaCod = Exam.ExaCod;
    ExaSes_GetDataOfSessionByCod (&Session);
@@ -406,7 +407,7 @@ void ExaRes_ShowAllResultsInExa (void)
    /***** Get parameters *****/
    Exa_GetParams (&Exams);
    if (Exams.ExaCod <= 0)
-      Lay_WrongExamExit ();
+      Err_WrongExamExit ();
    Exam.ExaCod = Exams.ExaCod;
    Exa_GetDataOfExamByCod (&Exam);
    Exams.ExaCod = Exam.ExaCod;
@@ -493,10 +494,10 @@ void ExaRes_ShowAllResultsInSes (void)
    /***** Get parameters *****/
    Exa_GetParams (&Exams);
    if (Exams.ExaCod <= 0)
-      Lay_WrongExamExit ();
+      Err_WrongExamExit ();
    Exam.ExaCod = Exams.ExaCod;
    if ((Session.SesCod = ExaSes_GetParamSesCod ()) <= 0)
-      Lay_WrongExamSessionExit ();
+      Err_WrongExamSessionExit ();
 
    /***** Get exam data and session *****/
    Exa_GetDataOfExamByCod (&Exam);
@@ -777,7 +778,7 @@ static void ExaRes_BuildExamsSelectedCommas (struct Exa_Exams *Exams,
    /***** Allocate memory for subquery of exams selected *****/
    MaxLength = (size_t) Exams->NumSelected * (Cns_MAX_DECIMAL_DIGITS_LONG + 1);
    if ((*ExamsSelectedCommas = malloc (MaxLength + 1)) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Build subquery with list of selected exams *****/
    (*ExamsSelectedCommas)[0] = '\0';
@@ -845,12 +846,12 @@ static void ExaRes_ShowResults (struct Exa_Exams *Exams,
    if (SesCod > 0)	// One unique session
      {
       if (asprintf (&SesSubQuery," AND exa_prints.SesCod=%ld",SesCod) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
      }
    else			// All sessions of selected exams
      {
       if (asprintf (&SesSubQuery,"%s","") < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
      }
 
    /***** Subquery: get hidden sessions?
@@ -861,11 +862,11 @@ static void ExaRes_ShowResults (struct Exa_Exams *Exams,
      {
       case Usr_ME:	// A student watching her/his results
          if (asprintf (&HidSesSubQuery," AND exa_sessions.Hidden='N'") < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 	 break;
       default:		// A teacher/admin watching the results of other users
 	 if (asprintf (&HidSesSubQuery,"%s","") < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 	 break;
      }
 
@@ -873,7 +874,7 @@ static void ExaRes_ShowResults (struct Exa_Exams *Exams,
    if (ExaCod > 0)			// One unique exams
      {
       if (asprintf (&ExaSubQuery," AND exa_sessions.ExaCod=%ld",ExaCod) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
      }
    else if (ExamsSelectedCommas)
      {
@@ -881,18 +882,18 @@ static void ExaRes_ShowResults (struct Exa_Exams *Exams,
 	{
 	 if (asprintf (&ExaSubQuery," AND exa_sessions.ExaCod IN (%s)",
 		       ExamsSelectedCommas) < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 	}
       else
 	{
 	 if (asprintf (&ExaSubQuery,"%s","") < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 	}
      }
    else					// All exams
      {
       if (asprintf (&ExaSubQuery,"%s","") < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
      }
 
    /***** Subquery: get hidden exams?
@@ -903,11 +904,11 @@ static void ExaRes_ShowResults (struct Exa_Exams *Exams,
      {
       case Usr_ME:	// A student watching her/his results
          if (asprintf (&HidExaSubQuery," AND exa_exams.Hidden='N'") < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 	 break;
       default:		// A teacher/admin watching the results of other users
 	 if (asprintf (&HidExaSubQuery,"%s","") < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 	 break;
      }
 
@@ -951,7 +952,7 @@ static void ExaRes_ShowResults (struct Exa_Exams *Exams,
 	{
 	 /* Get print code (row[0]) */
 	 if ((Print.PrnCod = DB_GetNextCode (mysql_res)) <= 0)
-	    Lay_WrongExamExit ();
+	    Err_WrongExamExit ();
 
 	 /* Get print data */
 	 ExaPrn_GetDataOfPrintByPrnCod (&Print);
@@ -975,7 +976,7 @@ static void ExaRes_ShowResults (struct Exa_Exams *Exams,
 	   {
 	    UniqueId++;
 	    if (asprintf (&Id,"exa_res_time_%u_%u",(unsigned) StartEndTime,UniqueId) < 0)
-	       Lay_NotEnoughMemoryExit ();
+	       Err_NotEnoughMemoryExit ();
 	    HTM_TD_Begin ("id =\"%s\" class=\"DAT LT COLOR%u\"",
 			  Id,Gbl.RowEvenOdd);
 	    Dat_WriteLocalDateHMSFromUTC (Id,Print.TimeUTC[StartEndTime],
@@ -1457,9 +1458,9 @@ static void ExaRes_ShowExamResult (const struct Exa_Exam *Exam,
    if (!Usr_ChkUsrCodAndGetAllUsrDataFromUsrCod (UsrDat,
                                                  Usr_DONT_GET_PREFS,
                                                  Usr_DONT_GET_ROLE_IN_CURRENT_CRS))
-      Lay_WrongUserExit ();
+      Err_WrongUserExit ();
    if (!Usr_CheckIfICanViewTstExaMchResult (UsrDat))
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Begin table *****/
    HTM_TABLE_BeginWideMarginPadding (10);
@@ -1674,7 +1675,7 @@ static void ExaRes_ShowExamResultTime (struct ExaPrn_Print *Print)
 
       /***** Time *****/
       if (asprintf (&Id,"match_%u",(unsigned) StartEndTime) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       HTM_TD_Begin ("id=\"%s\" class=\"DAT LB\"",Id);
       Dat_WriteLocalDateHMSFromUTC (Id,Print->TimeUTC[StartEndTime],
 				    Gbl.Prefs.DateFormat,Dat_SEPARATOR_COMMA,
diff --git a/swad_exam_session.c b/swad_exam_session.c
index 9cbb49a5..f19f5624 100644
--- a/swad_exam_session.c
+++ b/swad_exam_session.c
@@ -34,6 +34,7 @@
 
 #include "swad_database.h"
 #include "swad_date.h"
+#include "swad_error.h"
 #include "swad_exam.h"
 #include "swad_exam_print.h"
 #include "swad_exam_result.h"
@@ -163,7 +164,7 @@ void ExaSes_ListSessions (struct Exa_Exams *Exams,
      {
       case Rol_STD:
          if (asprintf (&HiddenSubQuery," AND Hidden='N'") < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 	 break;
       case Rol_NET:
       case Rol_TCH:
@@ -172,10 +173,10 @@ void ExaSes_ListSessions (struct Exa_Exams *Exams,
       case Rol_INS_ADM:
       case Rol_SYS_ADM:
 	 if (asprintf (&HiddenSubQuery,"%s","") < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 	 break;
       default:
-	 Lay_WrongRoleExit ();
+	 Err_WrongRoleExit ();
 	 break;
      }
 
@@ -193,11 +194,11 @@ void ExaSes_ListSessions (struct Exa_Exams *Exams,
 				      " WHERE grp_users.UsrCod=%ld"
 				        " AND exa_groups.GrpCod=grp_users.GrpCod))",
 		     Gbl.Usrs.Me.UsrDat.UsrCod) < 0)
-	  Lay_NotEnoughMemoryExit ();
+	  Err_NotEnoughMemoryExit ();
       }
     else	// Gbl.Crs.Grps.WhichGrps == Grp_ALL_GROUPS
        if (asprintf (&GroupsSubQuery,"%s","") < 0)
-	  Lay_NotEnoughMemoryExit ();
+	  Err_NotEnoughMemoryExit ();
 
    /***** Get data of sessions from database *****/
    NumSessions = (unsigned)
@@ -402,7 +403,7 @@ static void ExaSes_ListOneOrMoreSessions (struct Exa_Exams *Exams,
 	{
 	 /***** Build anchor string *****/
 	 if (asprintf (&Anchor,"evt_%ld_%ld",Exam->ExaCod,Session.SesCod) < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Begin row for this exam session ****/
 	 HTM_TR_Begin (NULL);
@@ -591,7 +592,7 @@ static void ExaSes_ListOneOrMoreSessionsTimes (const struct ExaSes_Session *Sess
 					     "DATE_RED");
 
       if (asprintf (&Id,"exa_time_%u_%u",(unsigned) StartEndTime,UniqueId) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       HTM_TD_Begin ("id=\"%s\" class=\"%s LT COLOR%u\"",
 		    Id,Color,Gbl.RowEvenOdd);
       Dat_WriteLocalDateHMSFromUTC (Id,Session->TimeUTC[StartEndTime],
@@ -737,7 +738,7 @@ static void ExaSes_ListOneOrMoreSessionsResult (struct Exa_Exams *Exams,
 	 ExaSes_ListOneOrMoreSessionsResultTch (Exams,Session);
 	 break;
       default:
-	 Lay_WrongRoleExit ();
+	 Err_WrongRoleExit ();
 	 break;
      }
 
@@ -821,7 +822,7 @@ void ExaSes_ToggleVisResultsSesUsr (void)
 
    /***** Check if visibility of session results can be changed *****/
    if (!ExaSes_CheckIfVisibilityOfResultsCanBeChanged (&Session))
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Toggle visibility of exam session results *****/
    Session.ShowUsrResults = !Session.ShowUsrResults;
@@ -870,11 +871,11 @@ static void ExaSes_GetSessionDataFromRow (MYSQL_RES *mysql_res,
    /***** Get session data *****/
    /* Code of the session (row[0]) */
    if ((Session->SesCod = Str_ConvertStrCodToLongCod (row[0])) <= 0)
-      Lay_WrongExamSessionExit ();
+      Err_WrongExamSessionExit ();
 
    /* Code of the exam (row[1]) */
    if ((Session->ExaCod = Str_ConvertStrCodToLongCod (row[1])) <= 0)
-      Lay_WrongExamExit ();
+      Err_WrongExamExit ();
 
    /* Get whether the session is hidden (row[2]) */
    Session->Hidden = (row[2][0] == 'Y');
@@ -956,7 +957,7 @@ void ExaSes_RemoveSession (void)
 
    /***** Check if I can remove this exam session *****/
    if (!ExaSes_CheckIfICanEditThisSession (&Session))
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Remove the exam session from all database tables *****/
    ExaSes_RemoveSessionFromAllTables (Session.SesCod);
@@ -1157,7 +1158,7 @@ void ExaSes_HideSession (void)
 
    /***** Check if I can remove this exam session *****/
    if (!ExaSes_CheckIfICanEditThisSession (&Session))
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Hide session *****/
    DB_QueryUPDATE ("can not hide exam sessions",
@@ -1197,7 +1198,7 @@ void ExaSes_UnhideSession (void)
 
    /***** Check if I can remove this exam session *****/
    if (!ExaSes_CheckIfICanEditThisSession (&Session))
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Unhide session *****/
    DB_QueryUPDATE ("can not unhide exam session",
@@ -1250,22 +1251,22 @@ void ExaSes_GetAndCheckParameters (struct Exa_Exams *Exams,
    /***** Get parameters *****/
    Exa_GetParams (Exams);
    if (Exams->ExaCod <= 0)
-      Lay_WrongExamExit ();
+      Err_WrongExamExit ();
    Exam->ExaCod = Exams->ExaCod;
    Grp_GetParamWhichGroups ();
    if ((Session->SesCod = ExaSes_GetParamSesCod ()) <= 0)
-      Lay_WrongExamSessionExit ();
+      Err_WrongExamSessionExit ();
 
    /***** Get exam data from database *****/
    Exa_GetDataOfExamByCod (Exam);
    if (Exam->CrsCod != Gbl.Hierarchy.Crs.CrsCod)
-      Lay_WrongExamExit ();
+      Err_WrongExamExit ();
    Exams->ExaCod = Exam->ExaCod;
 
    /***** Get set data from database *****/
    ExaSes_GetDataOfSessionByCod (Session);
    if (Session->ExaCod != Exam->ExaCod)
-      Lay_WrongSetExit ();
+      Err_WrongSetExit ();
    Exams->SesCod = Session->SesCod;
   }
 
@@ -1445,7 +1446,7 @@ void ExaSes_RequestCreatOrEditSession (void)
    /***** Get parameters *****/
    Exa_GetParams (&Exams);
    if (Exams.ExaCod <= 0)
-      Lay_WrongExamExit ();
+      Err_WrongExamExit ();
    Exam.ExaCod = Exams.ExaCod;
    Grp_GetParamWhichGroups ();
    Session.SesCod = ExaSes_GetParamSesCod ();
@@ -1454,7 +1455,7 @@ void ExaSes_RequestCreatOrEditSession (void)
    /***** Get exam data from database *****/
    Exa_GetDataOfExamByCod (&Exam);
    if (Exam.CrsCod != Gbl.Hierarchy.Crs.CrsCod)
-      Lay_WrongExamExit ();
+      Err_WrongExamExit ();
    Exams.ExaCod = Exam.ExaCod;
 
    /***** Get session data *****/
@@ -1466,7 +1467,7 @@ void ExaSes_RequestCreatOrEditSession (void)
       /* Get session data from database */
       ExaSes_GetDataOfSessionByCod (&Session);
       if (Exam.ExaCod != Session.ExaCod)
-	 Lay_WrongExamExit ();
+	 Err_WrongExamExit ();
       Exams.SesCod = Session.SesCod;
      }
 
@@ -1496,7 +1497,7 @@ void ExaSes_ReceiveFormSession (void)
    /***** Get main parameters *****/
    Exa_GetParams (&Exams);
    if (Exams.ExaCod <= 0)
-      Lay_WrongExamExit ();
+      Err_WrongExamExit ();
    Exam.ExaCod = Exams.ExaCod;
    Grp_GetParamWhichGroups ();
    Session.SesCod = ExaSes_GetParamSesCod ();
@@ -1505,7 +1506,7 @@ void ExaSes_ReceiveFormSession (void)
    /***** Get exam data from database *****/
    Exa_GetDataOfExamByCod (&Exam);
    if (Exam.CrsCod != Gbl.Hierarchy.Crs.CrsCod)
-      Lay_WrongExamExit ();
+      Err_WrongExamExit ();
    Exams.ExaCod = Exam.ExaCod;
 
    /***** Get session data from database *****/
@@ -1520,7 +1521,7 @@ void ExaSes_ReceiveFormSession (void)
       /* Get session data from database */
       ExaSes_GetDataOfSessionByCod (&Session);
       if (Session.ExaCod != Exam.ExaCod)
-	 Lay_WrongExamExit ();
+	 Err_WrongExamExit ();
       Exams.SesCod = Session.SesCod;
      }
 
diff --git a/swad_exam_set.c b/swad_exam_set.c
index 00e89244..9a5253fc 100644
--- a/swad_exam_set.c
+++ b/swad_exam_set.c
@@ -35,6 +35,7 @@
 #include <string.h>		// For string functions
 
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_exam.h"
 #include "swad_exam_result.h"
 #include "swad_exam_session.h"
@@ -367,7 +368,7 @@ void ExaSet_ReceiveFormSet (void)
    /***** Get parameters *****/
    Exa_GetParams (&Exams);
    if (Exams.ExaCod <= 0)
-      Lay_WrongExamExit ();
+      Err_WrongExamExit ();
    Set.ExaCod = Exam.ExaCod = Exams.ExaCod;
    Exams.SetCod = Set.SetCod = ExaSet_GetParamSetCod ();
    ItsANewSet = (Set.SetCod <= 0);
@@ -378,7 +379,7 @@ void ExaSet_ReceiveFormSet (void)
 
    /***** Check if exam is editable *****/
    if (!Exa_CheckIfEditable (&Exam))
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** If I can edit exams ==> receive set from form *****/
    ExaSet_ReceiveSetFieldsFromForm (&Set);
@@ -454,7 +455,7 @@ void ExaSet_ChangeSetTitle (void)
 
    /***** Check if I can edit exams *****/
    if (!Exa_CheckIfICanEditExams ())
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Reset exams context *****/
    Exa_ResetExams (&Exams);
@@ -466,7 +467,7 @@ void ExaSet_ChangeSetTitle (void)
 
    /***** Check if exam is editable *****/
    if (!Exa_CheckIfEditable (&Exam))
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Receive new title from form *****/
    Par_GetParToText ("Title",NewTitle,ExaSet_MAX_BYTES_TITLE);
@@ -498,7 +499,7 @@ void ExaSet_ChangeNumQstsToExam (void)
 
    /***** Check if I can edit exams *****/
    if (!Exa_CheckIfICanEditExams ())
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Reset exams context *****/
    Exa_ResetExams (&Exams);
@@ -510,7 +511,7 @@ void ExaSet_ChangeNumQstsToExam (void)
 
    /***** Check if exam is editable *****/
    if (!Exa_CheckIfEditable (&Exam))
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Get number of questions in set to appear in exam print *****/
    NumQstsToPrint = (unsigned) Par_GetParToUnsignedLong ("NumQstsToPrint",
@@ -667,7 +668,7 @@ void ExaSet_RequestCreatOrEditSet (void)
 
    /***** Check if I can edit exams *****/
    if (!Exa_CheckIfICanEditExams ())
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Reset exams context *****/
    Exa_ResetExams (&Exams);
@@ -677,7 +678,7 @@ void ExaSet_RequestCreatOrEditSet (void)
    /***** Get parameters *****/
    Exa_GetParams (&Exams);
    if (Exams.ExaCod <= 0)
-      Lay_WrongExamExit ();
+      Err_WrongExamExit ();
    Exam.ExaCod = Exams.ExaCod;
    Exams.SetCod = Set.SetCod = ExaSet_GetParamSetCod ();
    ItsANewSet = (Set.SetCod <= 0);
@@ -785,7 +786,7 @@ static unsigned ExaSet_GetSetIndFromSetCod (long ExaCod,long SetCod)
 			" WHERE SetCod=%u"
 			  " AND ExaCod=%ld",	// Extra check
 			SetCod,ExaCod))
-      Lay_WrongSetExit ();
+      Err_WrongSetExit ();
 
    /***** Get set code (row[0]) *****/
    row = mysql_fetch_row (mysql_res);
@@ -814,7 +815,7 @@ static long ExaSet_GetSetCodFromSetInd (long ExaCod,unsigned SetInd)
 				ExaCod,
 				SetInd);
    if (SetCod <= 0)
-      Lay_WrongSetExit ();
+      Err_WrongSetExit ();
 
    return SetCod;
   }
@@ -1323,7 +1324,7 @@ Tst_AnswerType_t ExaSet_GetQstAnswerTypeFromDB (long QstCod)
 		        " FROM exa_set_questions"
 		       " WHERE QstCod=%ld",
 		       QstCod))
-      Lay_WrongQuestionExit ();
+      Err_WrongQuestionExit ();
 
    /* Get type of answer */
    row = mysql_fetch_row (mysql_res);
@@ -1414,7 +1415,7 @@ void ExaSet_GetQstDataFromDB (struct Tst_Question *Question)
 	       break;
 	    case Tst_ANS_FLOAT:
 	       if (Question->Answer.NumOptions != 2)
-		  Lay_WrongAnswerExit ();
+		  Err_WrongAnswerExit ();
 	       Question->Answer.FloatingPoint[NumOpt] = Str_GetDoubleFromStr (row[1]);
 	       break;
 	    case Tst_ANS_TRUE_FALSE:
@@ -1426,7 +1427,7 @@ void ExaSet_GetQstDataFromDB (struct Tst_Question *Question)
 	    case Tst_ANS_TEXT:
 	       /* Check number of options */
 	       if (Question->Answer.NumOptions > Tst_MAX_OPTIONS_PER_QUESTION)
-		  Lay_WrongAnswerExit ();
+		  Err_WrongAnswerExit ();
 
 	       /*  Allocate space for text and feedback */
 	       if (!Tst_AllocateTextChoiceAnswer (Question,NumOpt))
@@ -1464,7 +1465,7 @@ void ExaSet_GetQstDataFromDB (struct Tst_Question *Question)
    DB_FreeMySQLResult (&mysql_res);
 
    if (!QuestionExists)
-      Lay_WrongQuestionExit ();
+      Err_WrongQuestionExit ();
   }
 
 /*****************************************************************************/
@@ -1596,7 +1597,7 @@ void ExaSet_AddQstsToSet (void)
 	 /* Get next code */
 	 Par_GetNextStrUntilSeparParamMult (&Ptr,LongStr,Cns_MAX_DECIMAL_DIGITS_LONG);
 	 if (sscanf (LongStr,"%ld",&QstCod) != 1)
-	    Lay_WrongQuestionExit ();
+	    Err_WrongQuestionExit ();
 
 	 ExaSet_CopyQstFromBankToExamSet (&Set,QstCod);
 	}
@@ -1621,7 +1622,7 @@ static void ExaSet_AllocateListSelectedQuestions (struct Exa_Exams *Exams)
    if (!Exams->ListQuestions)
      {
       if ((Exams->ListQuestions = malloc (ExaSet_MAX_BYTES_LIST_SELECTED_QUESTIONS + 1)) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
       Exams->ListQuestions[0] = '\0';
      }
   }
@@ -1756,7 +1757,7 @@ void ExaSet_RequestRemoveSet (void)
 
    /***** Check if exam is editable *****/
    if (!Exa_CheckIfEditable (&Exam))
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Show question and button to remove question *****/
    Ale_ShowAlertAndButton (ActRemExaSet,NULL,NULL,
@@ -1791,7 +1792,7 @@ void ExaSet_RemoveSet (void)
 
    /***** Check if exam is editable *****/
    if (!Exa_CheckIfEditable (&Exam))
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Remove the set from all the tables *****/
    /* Remove questions associated to set */
@@ -1813,7 +1814,7 @@ void ExaSet_RemoveSet (void)
 		   Set.SetCod,
 		   Set.ExaCod);
    if (!mysql_affected_rows (&Gbl.mysql))
-      Lay_ShowErrorAndExit ("The set to be removed does not exist.");
+      Err_ShowErrorAndExit ("The set to be removed does not exist.");
 
    /* Change index of sets greater than this */
    DB_QueryUPDATE ("can not update indexes of sets",
@@ -1855,7 +1856,7 @@ void ExaSet_MoveUpSet (void)
 
    /***** Check if exam is editable *****/
    if (!Exa_CheckIfEditable (&Exam))
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Get set index *****/
    SetIndBottom = ExaSet_GetSetIndFromSetCod (Exam.ExaCod,Set.SetCod);
@@ -1866,7 +1867,7 @@ void ExaSet_MoveUpSet (void)
       /* Indexes of sets to be exchanged */
       SetIndTop = ExaSet_GetPrevSetIndexInExam (Exam.ExaCod,SetIndBottom);
       if (!SetIndTop)
-	 Lay_ShowErrorAndExit ("Wrong set index.");
+	 Err_ShowErrorAndExit ("Wrong set index.");
 
       /* Exchange sets */
       ExaSet_ExchangeSets (Exam.ExaCod,SetIndTop,SetIndBottom);
@@ -1903,7 +1904,7 @@ void ExaSet_MoveDownSet (void)
 
    /***** Check if exam is editable *****/
    if (!Exa_CheckIfEditable (&Exam))
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Get set index *****/
    SetIndTop = ExaSet_GetSetIndFromSetCod (Exam.ExaCod,Set.SetCod);
@@ -1917,7 +1918,7 @@ void ExaSet_MoveDownSet (void)
       /* Indexes of sets to be exchanged */
       SetIndBottom = ExaSet_GetNextSetIndexInExam (Exam.ExaCod,SetIndTop);
       if (!SetIndBottom)
-	 Lay_ShowErrorAndExit ("Wrong set index.");
+	 Err_ShowErrorAndExit ("Wrong set index.");
 
       /* Exchange sets */
       ExaSet_ExchangeSets (Exam.ExaCod,SetIndTop,SetIndBottom);
@@ -2008,7 +2009,7 @@ void ExaSet_RemoveQstFromSet (void)
 		   QstCod,
 		   Set.SetCod);
    if (!mysql_affected_rows (&Gbl.mysql))
-      Lay_WrongQuestionExit ();
+      Err_WrongQuestionExit ();
 
    /***** Write message *****/
    Ale_ShowAlert (Ale_SUCCESS,Txt_Question_removed);
@@ -2141,22 +2142,22 @@ static void ExaSet_GetAndCheckParameters (struct Exa_Exams *Exams,
    /***** Get parameters *****/
    Exa_GetParams (Exams);
    if (Exams->ExaCod <= 0)
-      Lay_WrongExamExit ();
+      Err_WrongExamExit ();
    Exam->ExaCod = Exams->ExaCod;
    Grp_GetParamWhichGroups ();
    if ((Set->SetCod = ExaSet_GetParamSetCod ()) <= 0)
-      Lay_WrongSetExit ();
+      Err_WrongSetExit ();
 
    /***** Get exam data from database *****/
    Exa_GetDataOfExamByCod (Exam);
    if (Exam->CrsCod != Gbl.Hierarchy.Crs.CrsCod)
-      Lay_WrongExamExit ();
+      Err_WrongExamExit ();
    Exams->ExaCod = Exam->ExaCod;
 
    /***** Get set data from database *****/
    ExaSet_GetDataOfSetByCod (Set);
    if (Set->ExaCod != Exam->ExaCod)
-      Lay_WrongSetExit ();
+      Err_WrongSetExit ();
    Exams->SetCod = Set->SetCod;
   }
 
diff --git a/swad_figure.c b/swad_figure.c
index 42447953..6b722599 100644
--- a/swad_figure.c
+++ b/swad_figure.c
@@ -34,6 +34,7 @@
 #include "swad_agenda.h"
 #include "swad_box.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_figure.h"
 #include "swad_figure_cache.h"
 #include "swad_file_browser.h"
@@ -674,7 +675,7 @@ static void Fig_GetAndShowHierarchyWithInss (void)
       case Hie_Lvl_CRS:
 	 break;
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 break;
      }
 
@@ -717,7 +718,7 @@ static void Fig_GetAndShowHierarchyWithCtrs (void)
       case Hie_Lvl_CRS:
 	 break;
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 break;
      }
 
@@ -766,7 +767,7 @@ static void Fig_GetAndShowHierarchyWithDegs (void)
       case Hie_Lvl_CRS:
 	 break;
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 break;
      }
 
@@ -823,7 +824,7 @@ static void Fig_GetAndShowHierarchyWithCrss (void)
       case Hie_Lvl_CRS:
 	 break;
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 break;
      }
 
@@ -904,7 +905,7 @@ static void Fig_GetAndShowHierarchyWithUsrs (Rol_Role_t Role)
          NumCrssWithUsrs = Crs_GetCachedNumCrssWithUsrs (Role,SubQuery,Hie_Lvl_CRS,Gbl.Hierarchy.Crs.CrsCod);
 	 break;
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 break;
      }
 
@@ -962,7 +963,7 @@ static void Fig_GetAndShowHierarchyTotal (void)
      case Hie_Lvl_CRS:
 	 break;
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 break;
      }
 
@@ -1115,7 +1116,7 @@ static void Fig_GetAndShowInssOrderedByNumCtrs (void)
 			 Gbl.Hierarchy.Ins.InsCod);
          break;
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 break;
      }
 
@@ -1191,7 +1192,7 @@ static void Fig_GetAndShowInssOrderedByNumDegs (void)
 			 Gbl.Hierarchy.Ins.InsCod);
          break;
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 break;
      }
 
@@ -1273,7 +1274,7 @@ static void Fig_GetAndShowInssOrderedByNumCrss (void)
 			 Gbl.Hierarchy.Ins.InsCod);
          break;
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 break;
      }
 
@@ -1361,7 +1362,7 @@ static void Fig_GetAndShowInssOrderedByNumUsrsInCrss (void)
 			 Gbl.Hierarchy.Ins.InsCod);
          break;
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 break;
      }
 
@@ -1432,7 +1433,7 @@ static void Fig_GetAndShowInssOrderedByNumUsrsWhoClaimToBelongToThem (void)
 			 Gbl.Hierarchy.Ins.InsCod);
          break;
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 NumInss = 0;	// Not reached. Initialized to avoid warning.
 	 break;
      }
@@ -1577,11 +1578,11 @@ static unsigned Fig_GetInsAndStat (struct Ins_Instit *Ins,MYSQL_RES *mysql_res)
    /***** Get data of this institution (row[0]) *****/
    Ins->InsCod = Str_ConvertStrCodToLongCod (row[0]);
    if (!Ins_GetDataOfInstitutionByCod (Ins))
-      Lay_WrongInstitExit ();
+      Err_WrongInstitExit ();
 
    /***** Get statistic (row[1]) *****/
    if (sscanf (row[1],"%u",&NumberThisRow) != 1)
-      Lay_ShowErrorAndExit ("Error in statistic");
+      Err_ShowErrorAndExit ("Error in statistic");
 
    return NumberThisRow;
   }
@@ -1800,7 +1801,7 @@ static void Fig_GetSizeOfFileZoneFromDB (Hie_Lvl_Level_t Scope,
 			       (unsigned) FileBrowser);
 	       break;
 	    default:
-	       Lay_WrongFileBrowserExit ();
+	       Err_WrongFileBrowserExit ();
 	       break;
 	   }
          break;
@@ -1978,7 +1979,7 @@ static void Fig_GetSizeOfFileZoneFromDB (Hie_Lvl_Level_t Scope,
 			       (unsigned) FileBrowser);
 	       break;
 	    default:
-	       Lay_WrongFileBrowserExit ();
+	       Err_WrongFileBrowserExit ();
 	       break;
 	   }
          break;
@@ -2144,7 +2145,7 @@ static void Fig_GetSizeOfFileZoneFromDB (Hie_Lvl_Level_t Scope,
 			       (unsigned) FileBrowser);
 	       break;
 	    default:
-	       Lay_WrongFileBrowserExit ();
+	       Err_WrongFileBrowserExit ();
 	       break;
 	   }
          break;
@@ -2298,7 +2299,7 @@ static void Fig_GetSizeOfFileZoneFromDB (Hie_Lvl_Level_t Scope,
 			       (unsigned) FileBrowser);
 	       break;
 	    default:
-	       Lay_WrongFileBrowserExit ();
+	       Err_WrongFileBrowserExit ();
 	       break;
 	   }
          break;
@@ -2440,7 +2441,7 @@ static void Fig_GetSizeOfFileZoneFromDB (Hie_Lvl_Level_t Scope,
 			       (unsigned) FileBrowser);
 	       break;
 	    default:
-	       Lay_WrongFileBrowserExit ();
+	       Err_WrongFileBrowserExit ();
 	       break;
 	   }
          break;
@@ -2570,12 +2571,12 @@ static void Fig_GetSizeOfFileZoneFromDB (Hie_Lvl_Level_t Scope,
 			       (unsigned) FileBrowser);
 	       break;
 	    default:
-	       Lay_WrongFileBrowserExit ();
+	       Err_WrongFileBrowserExit ();
 	       break;
 	   }
          break;
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 break;
      }
 
@@ -2591,37 +2592,37 @@ static void Fig_GetSizeOfFileZoneFromDB (Hie_Lvl_Level_t Scope,
    /* Get number of courses (row[0]) */
    if (row[0])
       if (sscanf (row[0],"%d",&(SizeOfFileZones->NumCrss)) != 1)
-         Lay_ShowErrorAndExit ("Error when getting number of courses.");
+         Err_ShowErrorAndExit ("Error when getting number of courses.");
 
    /* Get number of groups (row[1]) */
    if (row[1])
       if (sscanf (row[1],"%d",&(SizeOfFileZones->NumGrps)) != 1)
-         Lay_ShowErrorAndExit ("Error when getting number of groups.");
+         Err_ShowErrorAndExit ("Error when getting number of groups.");
 
    /* Get number of users (row[2]) */
    if (row[2])
       if (sscanf (row[2],"%d",&(SizeOfFileZones->NumUsrs)) != 1)
-         Lay_ShowErrorAndExit ("Error when getting number of users.");
+         Err_ShowErrorAndExit ("Error when getting number of users.");
 
    /* Get maximum number of levels (row[3]) */
    if (row[3])
       if (sscanf (row[3],"%u",&(SizeOfFileZones->MaxLevels)) != 1)
-         Lay_ShowErrorAndExit ("Error when getting maximum number of levels.");
+         Err_ShowErrorAndExit ("Error when getting maximum number of levels.");
 
    /* Get number of folders (row[4]) */
    if (row[4])
       if (sscanf (row[4],"%lu",&(SizeOfFileZones->NumFolders)) != 1)
-         Lay_ShowErrorAndExit ("Error when getting number of folders.");
+         Err_ShowErrorAndExit ("Error when getting number of folders.");
 
    /* Get number of files (row[5]) */
    if (row[5])
       if (sscanf (row[5],"%lu",&(SizeOfFileZones->NumFiles)) != 1)
-         Lay_ShowErrorAndExit ("Error when getting number of files.");
+         Err_ShowErrorAndExit ("Error when getting number of files.");
 
    /* Get total size (row[6]) */
    if (row[6])
       if (sscanf (row[6],"%llu",&(SizeOfFileZones->Size)) != 1)
-         Lay_ShowErrorAndExit ("Error when getting toal size.");
+         Err_ShowErrorAndExit ("Error when getting toal size.");
 
    /* Free structure that stores the query result */
    DB_FreeMySQLResult (&mysql_res);
@@ -3079,7 +3080,7 @@ static void Fig_GetNumberOfOERsFromDB (Hie_Lvl_Level_t Scope,
 			 (unsigned) License);
          break;
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 break;
      }
 
@@ -3099,7 +3100,7 @@ static void Fig_GetNumberOfOERsFromDB (Hie_Lvl_Level_t Scope,
 
       /* Get number of files (row[1]) */
       if (sscanf (row[1],"%lu",&NumFiles[Public]) != 1)
-         Lay_ShowErrorAndExit ("Error when getting number of files.");
+         Err_ShowErrorAndExit ("Error when getting number of files.");
      }
 
    /* Free structure that stores the query result */
@@ -3681,7 +3682,7 @@ static void Fig_GetAndShowTimelineActivityStats (void)
 			    (unsigned) NoteType);
 	    break;
 	 default:
-	    Lay_WrongScopeExit ();
+	    Err_WrongScopeExit ();
 	    NumRows = 0;	// Initialized to avoid warning
 	    break;
 	}
@@ -3822,7 +3823,7 @@ static void Fig_GetAndShowTimelineActivityStats (void)
 		         Gbl.Hierarchy.Crs.CrsCod);
 	 break;
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 NumRows = 0;	// Initialized to avoid warning
 	 break;
      }
@@ -4016,7 +4017,7 @@ static void Fig_GetAndShowFollowStats (void)
 			   FieldDB[Fol]);
 	    break;
 	 default:
-	    Lay_WrongScopeExit ();
+	    Err_WrongScopeExit ();
 	    NumUsrs = 0;	// Not reached. Initialized to av oid warning
 	    break;
 	}
@@ -4155,7 +4156,7 @@ static void Fig_GetAndShowFollowStats (void)
 					    FieldDB[1 - Fol]);
 	    break;
 	 default:
-	    Lay_WrongScopeExit ();
+	    Err_WrongScopeExit ();
 	    Average = 0.0;	// Not reached
 	    break;
 	}
@@ -4283,7 +4284,7 @@ static void Fig_GetAndShowForumStats (void)
          Fig_ShowStatOfAForumType (For_FORUM_COURSE_TCHS,-1L,-1L,-1L,-1L,Gbl.Hierarchy.Crs.CrsCod,&FiguresForum);
          break;
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 break;
      }
 
@@ -4418,7 +4419,7 @@ static void Fig_WriteForumTitleAndStats (For_ForumType_t ForumType,
    HTM_TD_Begin ("class=\"BT\"");
    if (asprintf (&ForumName,"%s%s",
 		 ForumName1,ForumName2) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    Ico_PutIcon (Icon,ForumName,"ICO16x16");
    free (ForumName);
    HTM_TD_End ();
@@ -4581,7 +4582,7 @@ static void Fig_GetAndShowNumUsrsPerNotifyEvent (void)
       /* Get the number of users who want to be notified by email on this event, from database */
       if (asprintf (&SubQuery,"((usr_data.EmailNtfEvents & %u)<>0)",
 	            (1 << NotifyEvent)) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       NumUsrs[NotifyEvent] = Fig_GetNumUsrsWhoChoseAnOption (SubQuery);
       free (SubQuery);
 
@@ -4665,7 +4666,7 @@ static void Fig_GetAndShowNumUsrsPerNotifyEvent (void)
 			    (unsigned) NotifyEvent);
             break;
 	 default:
-	    Lay_WrongScopeExit ();
+	    Err_WrongScopeExit ();
 	    break;
         }
 
@@ -4675,7 +4676,7 @@ static void Fig_GetAndShowNumUsrsPerNotifyEvent (void)
       if (row[0])
         {
          if (sscanf (row[0],"%u",&NumEvents[NotifyEvent]) != 1)
-            Lay_ShowErrorAndExit ("Error when getting the number of notifications by email.");
+            Err_ShowErrorAndExit ("Error when getting the number of notifications by email.");
         }
       else
          NumEvents[NotifyEvent] = 0;
@@ -4684,7 +4685,7 @@ static void Fig_GetAndShowNumUsrsPerNotifyEvent (void)
       if (row[1])
         {
          if (sscanf (row[1],"%u",&NumMails[NotifyEvent]) != 1)
-            Lay_ShowErrorAndExit ("Error when getting the number of emails to notify events3.");
+            Err_ShowErrorAndExit ("Error when getting the number of emails to notify events3.");
         }
       else
          NumMails[NotifyEvent] = 0;
@@ -5146,7 +5147,7 @@ static void Fig_GetAndShowNumUsrsPerPrivacyForAnObject (const char *TxtObject,
 	 /* Get the number of users who have chosen this privacy option from database */
 	 if (asprintf (&SubQuery,"usr_data.%s='%s'",
 		       FieldName,Pri_VisibilityDB[Visibility]) < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 	 NumUsrs[Visibility] = Fig_GetNumUsrsWhoChoseAnOption (SubQuery);
 	 free (SubQuery);
 
@@ -5234,7 +5235,7 @@ static void Fig_GetAndShowNumUsrsPerCookies (void)
       /* Get number of users who have chosen this menu from database */
       if (asprintf (&SubQuery,"usr_data.ThirdPartyCookies='%c'",
 	            AcceptedInDB[i]) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       NumUsrs[i] = Fig_GetNumUsrsWhoChoseAnOption (SubQuery);
       free (SubQuery);
 
@@ -5310,7 +5311,7 @@ static void Fig_GetAndShowNumUsrsPerLanguage (void)
       /* Get the number of users who have chosen this language from database */
       if (asprintf (&SubQuery,"usr_data.Language='%s'",
 		    Lan_STR_LANG_ID[Lan]) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       NumUsrs[Lan] = Fig_GetNumUsrsWhoChoseAnOption (SubQuery);
       free (SubQuery);
 
@@ -5389,7 +5390,7 @@ static void Fig_GetAndShowNumUsrsPerFirstDayOfWeek (void)
 	 /* Get number of users who have chosen this first day of week from database */
 	 if (asprintf (&SubQuery,"usr_data.FirstDayOfWeek=%u",
 		       (unsigned) FirstDayOfWeek) < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 	 NumUsrs[FirstDayOfWeek] = Fig_GetNumUsrsWhoChoseAnOption (SubQuery);
 	 free (SubQuery);
 
@@ -5408,7 +5409,7 @@ static void Fig_GetAndShowNumUsrsPerFirstDayOfWeek (void)
 	 HTM_TD_Begin ("class=\"CM\"");
 	 if (asprintf (&Icon,"first-day-of-week-%u.png",
 		       FirstDayOfWeek) < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 	 Ico_PutIcon (Icon,
 		      Str_BuildStringStr (Txt_First_day_of_the_week_X,
 				          Txt_DAYS_SMALL[FirstDayOfWeek]),
@@ -5472,7 +5473,7 @@ static void Fig_GetAndShowNumUsrsPerDateFormat (void)
       /* Get number of users who have chosen this date format from database */
       if (asprintf (&SubQuery,"usr_data.DateFormat=%u",
 	            (unsigned) Format) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       NumUsrs[Format] = Fig_GetNumUsrsWhoChoseAnOption (SubQuery);
       free (SubQuery);
 
@@ -5550,7 +5551,7 @@ static void Fig_GetAndShowNumUsrsPerIconSet (void)
       /* Get the number of users who have chosen this icon set from database */
       if (asprintf (&SubQuery,"usr_data.IconSet='%s'",
 	            Ico_IconSetId[IconSet]) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       NumUsrs[IconSet] = Fig_GetNumUsrsWhoChoseAnOption (SubQuery);
       free (SubQuery);
 
@@ -5568,7 +5569,7 @@ static void Fig_GetAndShowNumUsrsPerIconSet (void)
       HTM_TD_Begin ("class=\"LM\"");
       if (asprintf (&URL,"%s/%s",
 		    Cfg_URL_ICON_SETS_PUBLIC,Ico_IconSetId[IconSet]) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       HTM_IMG (URL,"cog.svg",Ico_IconSetNames[IconSet],
 	       "class=\"ICO40x40\"");
       free (URL);
@@ -5631,7 +5632,7 @@ static void Fig_GetAndShowNumUsrsPerMenu (void)
       /* Get number of users who have chosen this menu from database */
       if (asprintf (&SubQuery,"usr_data.Menu=%u",
 	            (unsigned) Menu) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       NumUsrs[Menu] = Fig_GetNumUsrsWhoChoseAnOption (SubQuery);
       free (SubQuery);
 
@@ -5708,7 +5709,7 @@ static void Fig_GetAndShowNumUsrsPerTheme (void)
       /* Get number of users who have chosen this theme from database */
       if (asprintf (&SubQuery,"usr_data.Theme='%s'",
 		    The_ThemeId[Theme]) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       NumUsrs[Theme] = Fig_GetNumUsrsWhoChoseAnOption (SubQuery);
       free (SubQuery);
 
@@ -5726,7 +5727,7 @@ static void Fig_GetAndShowNumUsrsPerTheme (void)
       HTM_TD_Begin ("class=\"CM\"");
       if (asprintf (&URL,"%s/%s",
 		    Cfg_URL_ICON_THEMES_PUBLIC,The_ThemeId[Theme]) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       HTM_IMG (URL,"theme_32x20.gif",The_ThemeNames[Theme],
 	       "style=\"width:40px;height:25px;\"");
       free (URL);
@@ -5789,7 +5790,7 @@ static void Fig_GetAndShowNumUsrsPerSideColumns (void)
       /* Get the number of users who have chosen this layout of columns from database */
       if (asprintf (&SubQuery,"usr_data.SideCols=%u",
 	            SideCols) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       NumUsrs[SideCols] = Fig_GetNumUsrsWhoChoseAnOption (SubQuery);
       free (SubQuery);
 
@@ -5807,7 +5808,7 @@ static void Fig_GetAndShowNumUsrsPerSideColumns (void)
       HTM_TD_Begin ("class=\"CM\"");
       if (asprintf (&Icon,"layout%u%u_32x20.gif",
 		    SideCols >> 1,SideCols & 1) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       HTM_IMG (Cfg_URL_ICON_PUBLIC,Icon,Txt_LAYOUT_SIDE_COLUMNS[SideCols],
 	       "style=\"width:40px;height:25px;\"");
       free (Icon);
@@ -5925,7 +5926,7 @@ unsigned Fig_GetNumUsrsWhoChoseAnOption (const char *SubQuery)
 		        Gbl.Hierarchy.Crs.CrsCod,SubQuery);
 	 break;
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 NumUsrs = 0;	// Not reached. Initialized to avoid warning.
 	 break;
      }
diff --git a/swad_file.c b/swad_file.c
index c112518a..8dd10726 100644
--- a/swad_file.c
+++ b/swad_file.c
@@ -39,6 +39,7 @@
 
 #include "swad_config.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_global.h"
 #include "swad_file.h"
 #include "swad_string.h"
@@ -84,7 +85,7 @@ void Fil_CreateFileForHTMLOutput (void)
    if ((Gbl.F.Out = fopen (Gbl.HTMLOutput.FileName,"w+t")) == NULL)
      {
       Gbl.F.Out = stdout;
-      Lay_ShowErrorAndExit ("Can not create output file.");
+      Err_ShowErrorAndExit ("Can not create output file.");
      }
   }
 
@@ -118,7 +119,7 @@ bool Fil_ReadStdinIntoTmpFile (void)
    if ((Gbl.F.Tmp = tmpfile ()) == NULL)
      {
       Fil_EndOfReadingStdin ();
-      Lay_ShowErrorAndExit ("Can not create temporary file.");
+      Err_ShowErrorAndExit ("Can not create temporary file.");
      }
    for (TmpFileSize = 0;
 	!feof (stdin) && !FileIsTooBig && !TimeExceeded;
@@ -233,13 +234,13 @@ struct Param *Fil_StartReceptionOfFile (const char *ParamFile,
       return Param;
      }
    if (Param->FileName.Length > PATH_MAX)
-      Lay_ShowErrorAndExit ("Error while getting filename.");
+      Err_ShowErrorAndExit ("Error while getting filename.");
 
    /* Copy filename */
    fseek (Gbl.F.Tmp,Param->FileName.Start,SEEK_SET);
    if (fread (FileName,sizeof (char),Param->FileName.Length,Gbl.F.Tmp) !=
        Param->FileName.Length)
-      Lay_ShowErrorAndExit ("Error while getting filename.");
+      Err_ShowErrorAndExit ("Error while getting filename.");
    FileName[Param->FileName.Length] = '\0';
 
    /***** Get MIME type *****/
@@ -247,13 +248,13 @@ struct Param *Fil_StartReceptionOfFile (const char *ParamFile,
    if (Param->ContentType.Start == 0 ||
        Param->ContentType.Length == 0 ||
        Param->ContentType.Length > Brw_MAX_BYTES_MIME_TYPE)
-      Lay_ShowErrorAndExit ("Error while getting content type.");
+      Err_ShowErrorAndExit ("Error while getting content type.");
 
    /* Copy MIME type */
    fseek (Gbl.F.Tmp,Param->ContentType.Start,SEEK_SET);
    if (fread (MIMEType,sizeof (char),Param->ContentType.Length,Gbl.F.Tmp) !=
        Param->ContentType.Length)
-      Lay_ShowErrorAndExit ("Error while getting content type.");
+      Err_ShowErrorAndExit ("Error while getting content type.");
    MIMEType[Param->ContentType.Length] = '\0';
 
    return Param;
@@ -272,12 +273,12 @@ bool Fil_EndReceptionOfFile (char *FileNameDataTmp,struct Param *Param)
 
    /***** Open destination file *****/
    if ((FileDataTmp = fopen (FileNameDataTmp,"wb")) == NULL)
-      Lay_ShowErrorAndExit ("Can not open temporary file.");
+      Err_ShowErrorAndExit ("Can not open temporary file.");
 
    /***** Copy file *****/
    /* Go to start of source */
    if (Param->Value.Start == 0)
-      Lay_ShowErrorAndExit ("Error while copying file.");
+      Err_ShowErrorAndExit ("Error while copying file.");
    fseek (Gbl.F.Tmp,Param->Value.Start,SEEK_SET);
 
    /* Copy part of Gbl.F.Tmp to FileDataTmp */
@@ -336,7 +337,7 @@ void Fil_CreateUpdateFile (const char CurrentName[PATH_MAX + 1],
      {
       snprintf (ErrorMsg,sizeof (ErrorMsg),
                 "Can not create file <strong>%s</strong>.",NewName);
-      Lay_ShowErrorAndExit (ErrorMsg);
+      Err_ShowErrorAndExit (ErrorMsg);
      }
   }
 
@@ -360,14 +361,14 @@ void Fil_CloseUpdateFile (const char CurrentName[PATH_MAX + 1],
       snprintf (ErrorMsg,sizeof (ErrorMsg),
 	        "Can not rename the file <strong>%s</strong> as <strong>%s</strong>.",
                 CurrentName,OldName);
-      Lay_ShowErrorAndExit (ErrorMsg);
+      Err_ShowErrorAndExit (ErrorMsg);
      }
    if (rename (NewName,CurrentName)) // mv NewName CurrentName Ej: mv file.new file.html
      {
       snprintf (ErrorMsg,sizeof (ErrorMsg),
 	        "Can not rename the file <strong>%s</strong> as <strong>%s</strong>.",
                 NewName,CurrentName);
-      Lay_ShowErrorAndExit (ErrorMsg);
+      Err_ShowErrorAndExit (ErrorMsg);
      }
   }
 
@@ -397,7 +398,7 @@ void Fil_CreateDirIfNotExists (const char Path[PATH_MAX + 1])
         {
 	 snprintf (ErrorMsg,sizeof (ErrorMsg),
 	           "Can not create folder <strong>%s</strong>.",Path);
-	 Lay_ShowErrorAndExit (ErrorMsg);
+	 Err_ShowErrorAndExit (ErrorMsg);
         }
   }
 
@@ -418,7 +419,7 @@ void Fil_RemoveTree (const char Path[PATH_MAX + 1])
    if (Fil_CheckIfPathExists (Path))
      {
       if (lstat (Path,&FileStatus))	// On success ==> 0 is returned
-	 Lay_ShowErrorAndExit ("Can not get information about a file or folder.");
+	 Err_ShowErrorAndExit ("Can not get information about a file or folder.");
       else if (S_ISDIR (FileStatus.st_mode))		// It's a directory
 	{
 	 if (rmdir (Path))
@@ -447,7 +448,7 @@ void Fil_RemoveTree (const char Path[PATH_MAX + 1])
 		  free (FileList);
 		 }
 	       else
-		  Lay_ShowErrorAndExit ("Error while scanning directory.");
+		  Err_ShowErrorAndExit ("Error while scanning directory.");
 
 	       /***** Remove of new the directory, now empty *****/
 	       if (rmdir (Path))
@@ -459,13 +460,13 @@ void Fil_RemoveTree (const char Path[PATH_MAX + 1])
 	      {
 	       snprintf (ErrorMsg,sizeof (ErrorMsg),
 	                 "Can not remove folder %s.",Path);
-	       Lay_ShowErrorAndExit (ErrorMsg);
+	       Err_ShowErrorAndExit (ErrorMsg);
 	      }
 	   }
 	}
       else					// It's a file
 	 if (unlink (Path))
-	    Lay_ShowErrorAndExit ("Can not remove file.");
+	    Err_ShowErrorAndExit ("Can not remove file.");
      }
   }
 
@@ -516,7 +517,7 @@ void Fil_RemoveOldTmpFiles (const char *Path,time_t TimeToRemove,
 		  rmdir (Path);
 	   }
 	 else
-	    Lay_ShowErrorAndExit ("Error while scanning directory.");
+	    Err_ShowErrorAndExit ("Error while scanning directory.");
 	}
       else					// Not a directory
 	 if (FileStatus.st_mtime < Gbl.StartExecutionTimeUTC - TimeToRemove)
@@ -535,11 +536,11 @@ void Fil_FastCopyOfFiles (const char *PathSrc,const char *PathTgt)
 
    /***** Open source file *****/
    if ((FileSrc = fopen (PathSrc,"rb")) == NULL)
-      Lay_ShowErrorAndExit ("Can not open source file.");
+      Err_ShowErrorAndExit ("Can not open source file.");
 
    /***** Open destination file *****/
    if ((FileTgt = fopen (PathTgt,"wb")) == NULL)
-      Lay_ShowErrorAndExit ("Can not open target file.");
+      Err_ShowErrorAndExit ("Can not open target file.");
 
    /***** Copy source file into destination file *****/
    Fil_FastCopyOfOpenFiles (FileSrc,FileTgt);
diff --git a/swad_file_browser.c b/swad_file_browser.c
index b7d08119..4ad059c3 100644
--- a/swad_file_browser.c
+++ b/swad_file_browser.c
@@ -41,6 +41,7 @@
 #include "swad_box.h"
 #include "swad_config.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_figure.h"
 #include "swad_file_browser.h"
 #include "swad_file_extension.h"
@@ -1977,7 +1978,7 @@ void Brw_GetParAndInitFileBrowser (void)
 								  Brw_ADMI_MRK_CRS;
 	       break;
 	    default:
-	       Lay_WrongRoleExit ();
+	       Err_WrongRoleExit ();
 	       break;
 	   }
          break;
@@ -2079,7 +2080,7 @@ void Brw_GetParAndInitFileBrowser (void)
          Gbl.FileBrowser.Type = Brw_ADMI_BRF_USR;
          break;
       default:
-         Lay_ShowErrorAndExit ("The type of file browser can not be determined.");
+         Err_ShowErrorAndExit ("The type of file browser can not be determined.");
          break;
      }
 
@@ -2278,9 +2279,9 @@ static void Brw_GetDataCurrentGrp (void)
 	    /***** For security, check if group file zones are enabled,
 		   and check if I belongs to the selected group *****/
 	    if (!GrpDat.FileZones)
-	       Lay_ShowErrorAndExit ("The group has no file zones.");
+	       Err_ShowErrorAndExit ("The group has no file zones.");
 	    else if (!Grp_GetIfIBelongToGrp (Gbl.Crs.Grps.GrpCod))
-	       Lay_ShowErrorAndExit ("You don't have access to the group.");
+	       Err_ShowErrorAndExit ("You don't have access to the group.");
 	    break;
 	}
 
@@ -2378,7 +2379,7 @@ static void Brw_GetParamsPathInTreeAndFileName (void)
 
    /* Check if path contains ".." */
    if (strstr (Gbl.FileBrowser.FilFolLnk.Path,".."))	// ".." is not allowed in path
-      Lay_ShowErrorAndExit ("Wrong path.");
+      Err_ShowErrorAndExit ("Wrong path.");
 
    /***** Get the name of the file, folder or link *****/
    Gbl.FileBrowser.FilFolLnk.Type = Brw_IS_UNKNOWN;
@@ -2397,7 +2398,7 @@ static void Brw_GetParamsPathInTreeAndFileName (void)
 	                        Gbl.FileBrowser.FilFolLnk.Name,
                                 FileNameToShow);
 	 if (strstr (FileNameToShow,".."))	// ".." is not allowed in filename
-	    Lay_ShowErrorAndExit ("Wrong file name.");
+	    Err_ShowErrorAndExit ("Wrong file name.");
 	 break;
 	}
 
@@ -3361,13 +3362,13 @@ static void Brw_GetSelectedGroupData (struct GroupData *GrpDat,bool AbortOnError
       if (!GrpDat->FileZones)
         {
          if (AbortOnError)
-            Lay_ShowErrorAndExit ("The file browser is disabled.");
+            Err_ShowErrorAndExit ("The file browser is disabled.");
          GrpDat->GrpCod = -1L;
         }
       else if (!Grp_GetIfIBelongToGrp (GrpDat->GrpCod))
         {
          if (AbortOnError)
-            Lay_NoPermissionExit ();
+            Err_NoPermissionExit ();
          GrpDat->GrpCod = -1L;
         }
      }
@@ -3403,7 +3404,7 @@ static void Brw_ShowDataOwnerAsgWrk (struct UsrData *UsrDat)
 	       break;
 	    default:
 	       NextAction = ActUnk;
-	       Lay_WrongRoleExit ();
+	       Err_WrongRoleExit ();
 	       break;
 	   }
 	 Frm_BeginForm (NextAction);
@@ -4035,7 +4036,7 @@ static void Brw_WriteSubtitleOfFileBrowser (void)
 	       break;
 	    default:
 	       Subtitle[0] = '\0';
-	       Lay_WrongRoleExit ();
+	       Err_WrongRoleExit ();
 	       break;
 	   }
  	 break;
@@ -5148,7 +5149,7 @@ void Brw_CreateDirDownloadTmp (void)
    snprintf (PathUniqueDirR,sizeof (PathUniqueDirR),"%s/%s",
              PathUniqueDirL,Gbl.FileBrowser.TmpPubDir.R);
    if (mkdir (PathUniqueDirR,(mode_t) 0xFFF))
-      Lay_ShowErrorAndExit ("Can not create a temporary folder for download.");
+      Err_ShowErrorAndExit ("Can not create a temporary folder for download.");
 
    /* 4. Increase number of directory for next call */
    NumDir++;
@@ -5234,10 +5235,10 @@ static void Brw_GetAndUpdateDateLastAccFileBrowser (void)
       if (row[0] == NULL)
          Gbl.Usrs.Me.TimeLastAccToThisFileBrowser = 0;
       else if (sscanf (row[0],"%ld",&Gbl.Usrs.Me.TimeLastAccToThisFileBrowser) != 1)
-         Lay_ShowErrorAndExit ("Error when reading date-time of last access to a file browser.");
+         Err_ShowErrorAndExit ("Error when reading date-time of last access to a file browser.");
      }
    else
-      Lay_ShowErrorAndExit ("Error when getting date-time of last access to a file browser.");
+      Err_ShowErrorAndExit ("Error when getting date-time of last access to a file browser.");
 
    /***** Free structure that stores the query result *****/
    DB_FreeMySQLResult (&mysql_res);
@@ -5285,13 +5286,13 @@ static long Brw_GetGrpLastAccZone (const char *FieldNameDB)
       if (row[0])
         {
          if (sscanf (row[0],"%ld",&GrpCod) != 1)
-            Lay_ShowErrorAndExit ("Error when reading the group of your last access to a file browser.");
+            Err_ShowErrorAndExit ("Error when reading the group of your last access to a file browser.");
         }
       else
          GrpCod = -1L;
      }
    else
-      Lay_ShowErrorAndExit ("Error when getting the group of your last access to a file browser.");
+      Err_ShowErrorAndExit ("Error when getting the group of your last access to a file browser.");
 
    /***** Free structure that stores the query result *****/
    DB_FreeMySQLResult (&mysql_res);
@@ -5359,7 +5360,7 @@ static void Brw_CalcSizeOfDirRecursive (unsigned Level,char *Path)
 	    snprintf (PathFileRel,sizeof (PathFileRel),"%s/%s",
 		      Path,FileList[NumFile]->d_name);
 	    if (lstat (PathFileRel,&FileStatus))	// On success ==> 0 is returned
-	       Lay_ShowErrorAndExit ("Can not get information about a file or folder.");
+	       Err_ShowErrorAndExit ("Can not get information about a file or folder.");
 	    else if (S_ISDIR (FileStatus.st_mode))		// It's a directory
 	      {
 	       Gbl.FileBrowser.Size.NumFolds++;
@@ -5377,7 +5378,7 @@ static void Brw_CalcSizeOfDirRecursive (unsigned Level,char *Path)
       free (FileList);
      }
    else
-      Lay_ShowErrorAndExit ("Error while scanning directory.");
+      Err_ShowErrorAndExit ("Error while scanning directory.");
   }
 
 /*****************************************************************************/
@@ -5431,7 +5432,7 @@ static void Brw_ListDir (unsigned Level,const char *ParentRowId,
 
 	    /***** Get file or folder status *****/
 	    if (lstat (PathFileRel,&FileStatus))	// On success ==> 0 is returned
-	       Lay_ShowErrorAndExit ("Can not get information about a file or folder.");
+	       Err_ShowErrorAndExit ("Can not get information about a file or folder.");
 	    else if (S_ISDIR (FileStatus.st_mode))	// It's a directory
 	      {
 	       Gbl.FileBrowser.FilFolLnk.Type = Brw_IS_FOLDER;
@@ -5456,7 +5457,7 @@ static void Brw_ListDir (unsigned Level,const char *ParentRowId,
 		     free (SubdirFileList);
 		    }
 		  else
-		     Lay_ShowErrorAndExit ("Error while scanning directory.");
+		     Err_ShowErrorAndExit ("Error while scanning directory.");
 		 }
 
 	       /***** Write a row for the subdirectory *****/
@@ -5483,7 +5484,7 @@ static void Brw_ListDir (unsigned Level,const char *ParentRowId,
       free (FileList);
      }
    else
-      Lay_ShowErrorAndExit ("Error while scanning directory.");
+      Err_ShowErrorAndExit ("Error while scanning directory.");
   }
 
 /*****************************************************************************/
@@ -5601,7 +5602,7 @@ static bool Brw_WriteRowFileBrowser (unsigned Level,const char *RowId,
    /***** Start this row *****/
    if (asprintf (&Anchor,"fil_brw_%u_%s",
 		 Gbl.FileBrowser.Id,RowId) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    switch (IconThisRow)
      {
       case Brw_ICON_TREE_NOTHING:
@@ -6236,7 +6237,7 @@ static void Brw_PutIconFile (Brw_FileType_t FileType,const char *FileName,
      {
       if (asprintf (&URL,"%s32x32",
 		    CfG_URL_ICON_FILEXT_PUBLIC) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       for (DocType = 0, NotFound = true;
 	   DocType < Ext_NUM_FILE_EXT_ALLOWED && NotFound;
 	   DocType++)
@@ -6244,18 +6245,18 @@ static void Brw_PutIconFile (Brw_FileType_t FileType,const char *FileName,
 	   {
 	    if (asprintf (&Icon,"%s32x32.gif",
 			  Ext_FileExtensionsAllowed[DocType]) < 0)
-	       Lay_NotEnoughMemoryExit ();
+	       Err_NotEnoughMemoryExit ();
 	    if (asprintf (&Title,Txt_X_file,
 			  Ext_FileExtensionsAllowed[DocType]) < 0)
-	       Lay_NotEnoughMemoryExit ();
+	       Err_NotEnoughMemoryExit ();
 	    NotFound = false;
 	   }
       if (NotFound)
 	{
 	 if (asprintf (&Icon,"xxx32x32.gif") < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 	 if (asprintf (&Title,"%s","") < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 	}
 
       if (Input)
@@ -6371,7 +6372,7 @@ static void Brw_WriteFileName (unsigned Level,bool IsPublic)
 
       /* Link to the form and to the file */
       if (asprintf (&Class,"BT_LINK FILENAME %s",Gbl.FileBrowser.TxtStyle) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       HTM_BUTTON_SUBMIT_Begin ((Gbl.FileBrowser.Type == Brw_SHOW_MRK_CRS ||
 			        Gbl.FileBrowser.Type == Brw_SHOW_MRK_GRP) ? Txt_Check_marks_in_the_file :
 									    Txt_Download,
@@ -6436,7 +6437,7 @@ void Brw_CreateTmpPublicLinkToPrivateFile (const char *FullPathIncludingFile,
              Gbl.FileBrowser.TmpPubDir.R,
 	     FileName);
    if (symlink (FullPathIncludingFile,Link) != 0)
-      Lay_ShowErrorAndExit ("Can not create temporary link.");
+      Err_ShowErrorAndExit ("Can not create temporary link.");
   }
 
 /*****************************************************************************/
@@ -6461,7 +6462,7 @@ static void Brw_WriteDatesAssignment (void)
 
       /***** Write start date *****/
       if (asprintf (&Id,"asg_start_date_%u",UniqueId) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       HTM_SPAN_Begin ("id=\"%s\"",Id);
       Dat_WriteLocalDateHMSFromUTC (Id,Gbl.FileBrowser.Asg.TimeUTC[Dat_START_TIME],
 				    Gbl.Prefs.DateFormat,Dat_SEPARATOR_COMMA,
@@ -6474,7 +6475,7 @@ static void Brw_WriteDatesAssignment (void)
 
       /***** Write end date *****/
       if (asprintf (&Id,"asg_end_date_%u",UniqueId) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       HTM_SPAN_Begin ("id=\"%s\"",Id);
       Dat_WriteLocalDateHMSFromUTC (Id,Gbl.FileBrowser.Asg.TimeUTC[Dat_END_TIME],
 				    Gbl.Prefs.DateFormat,Dat_SEPARATOR_COMMA,
@@ -6518,7 +6519,7 @@ static void Brw_WriteFileSizeAndDate (struct FileMetadata *FileMetadata)
      {
       UniqueId++;
       if (asprintf (&Id,"filedate%u",UniqueId) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       HTM_SPAN_Begin ("id=\"%s\"",Id);
       HTM_SPAN_End ();
       Dat_WriteLocalDateHMSFromUTC (Id,FileMetadata->Time,
@@ -6598,7 +6599,7 @@ void Brw_AskRemFileFromTree (void)
                               FileNameToShow);
      }
    else
-      Lay_ShowErrorAndExit (Txt_You_can_not_remove_this_file_or_link);
+      Err_ShowErrorAndExit (Txt_You_can_not_remove_this_file_or_link);
 
    /***** Show again file browser *****/
    Brw_ShowAgainFileBrowserOrWorks ();
@@ -6627,7 +6628,7 @@ void Brw_RemFileFromTree (void)
 
       /***** Check if is a file/link or a folder *****/
       if (lstat (Path,&FileStatus))	// On success ==> 0 is returned
-	 Lay_ShowErrorAndExit ("Can not get information about a file or folder.");
+	 Err_ShowErrorAndExit ("Can not get information about a file or folder.");
       else if (S_ISREG (FileStatus.st_mode))		// It's a file or a link
         {
 	 /* Name of the file/link to be shown */
@@ -6649,10 +6650,10 @@ void Brw_RemFileFromTree (void)
 		        FileNameToShow);
         }
       else		// File / link not found
-         Lay_ShowErrorAndExit ("File / link not found.");
+         Err_ShowErrorAndExit ("File / link not found.");
      }
    else
-      Lay_ShowErrorAndExit (Txt_You_can_not_remove_this_file_or_link);
+      Err_ShowErrorAndExit (Txt_You_can_not_remove_this_file_or_link);
 
    /***** Show again file browser *****/
    Brw_ShowAgainFileBrowserOrWorks ();
@@ -6680,7 +6681,7 @@ void Brw_RemFolderFromTree (void)
 
       /***** Check if it's a file or a folder *****/
       if (lstat (Path,&FileStatus))	// On success ==> 0 is returned
-	 Lay_ShowErrorAndExit ("Can not get information about a file or folder.");
+	 Err_ShowErrorAndExit ("Can not get information about a file or folder.");
       else if (S_ISDIR (FileStatus.st_mode))		// It's a directory
 	 if (Brw_RemoveFolderFromDiskAndDB (Path,
                                             Gbl.FileBrowser.FilFolLnk.Full))
@@ -6688,7 +6689,7 @@ void Brw_RemFolderFromTree (void)
 	    if (errno == ENOTEMPTY)	// The directory is not empty
 	       Brw_AskConfirmRemoveFolderNotEmpty ();
 	    else	// The directory is empty
-               Lay_ShowErrorAndExit ("Can not remove folder.");
+               Err_ShowErrorAndExit ("Can not remove folder.");
            }
          else
            {
@@ -6702,10 +6703,10 @@ void Brw_RemFolderFromTree (void)
                            Gbl.FileBrowser.FilFolLnk.Name);
            }
       else		// Folder not found
-         Lay_ShowErrorAndExit ("Folder not found.");
+         Err_ShowErrorAndExit ("Folder not found.");
      }
    else
-      Lay_ShowErrorAndExit (Txt_You_can_not_remove_this_folder);
+      Err_ShowErrorAndExit (Txt_You_can_not_remove_this_folder);
 
    /***** Show again file browser *****/
    Brw_ShowAgainFileBrowserOrWorks ();
@@ -7160,7 +7161,7 @@ static bool Brw_GetMyClipboard (void)
    DB_FreeMySQLResult (&mysql_res);
 
    if (NumRows > 1)
-      Lay_WrongCopySrcExit ();
+      Err_WrongCopySrcExit ();
 
    return (bool) (NumRows == 1);
   }
@@ -7953,7 +7954,7 @@ static void Brw_PasteClipboard (void)
 		         (unsigned) Hie.Ins.InsCod,
 			 Gbl.FileBrowser.Clipboard.FilFolLnk.Full);
             else
-               Lay_WrongCopySrcExit ();
+               Err_WrongCopySrcExit ();
             break;
          case Brw_ADMI_DOC_CTR:
          case Brw_ADMI_SHR_CTR:
@@ -7965,7 +7966,7 @@ static void Brw_PasteClipboard (void)
 		         (unsigned) Hie.Ctr.CtrCod,
 			 Gbl.FileBrowser.Clipboard.FilFolLnk.Full);
             else
-               Lay_WrongCopySrcExit ();
+               Err_WrongCopySrcExit ();
             break;
          case Brw_ADMI_DOC_DEG:
          case Brw_ADMI_SHR_DEG:
@@ -7977,7 +7978,7 @@ static void Brw_PasteClipboard (void)
 		         (unsigned) Hie.Deg.DegCod,
 			 Gbl.FileBrowser.Clipboard.FilFolLnk.Full);
             else
-               Lay_WrongCopySrcExit ();
+               Err_WrongCopySrcExit ();
             break;
          case Brw_ADMI_DOC_CRS:
          case Brw_ADMI_TCH_CRS:
@@ -7989,7 +7990,7 @@ static void Brw_PasteClipboard (void)
                          Cfg_PATH_CRS_PRIVATE,Hie.Crs.CrsCod,
 			 Gbl.FileBrowser.Clipboard.FilFolLnk.Full);
             else
-               Lay_WrongCopySrcExit ();
+               Err_WrongCopySrcExit ();
             break;
          case Brw_ADMI_DOC_GRP:
          case Brw_ADMI_TCH_GRP:
@@ -8004,7 +8005,7 @@ static void Brw_PasteClipboard (void)
 			 GrpDat.GrpCod,
 			 Gbl.FileBrowser.Clipboard.FilFolLnk.Full);
             else
-               Lay_WrongCopySrcExit ();
+               Err_WrongCopySrcExit ();
             break;
          case Brw_ADMI_ASG_CRS:
          case Brw_ADMI_WRK_CRS:
@@ -8026,7 +8027,7 @@ static void Brw_PasteClipboard (void)
 	       Usr_UsrDataDestructor (&UsrDat);
               }
             else
-               Lay_WrongCopySrcExit ();
+               Err_WrongCopySrcExit ();
             break;
          case Brw_ADMI_ASG_USR:
          case Brw_ADMI_WRK_USR:
@@ -8038,7 +8039,7 @@ static void Brw_PasteClipboard (void)
 			 Gbl.Usrs.Me.UsrDat.UsrCod,
 			 Gbl.FileBrowser.Clipboard.FilFolLnk.Full);
             else
-               Lay_WrongCopySrcExit ();
+               Err_WrongCopySrcExit ();
             break;
          case Brw_ADMI_DOC_PRJ:
          case Brw_ADMI_ASS_PRJ:
@@ -8051,7 +8052,7 @@ static void Brw_PasteClipboard (void)
 			PrjCod,
 			Gbl.FileBrowser.Clipboard.FilFolLnk.Full);
 	    else
-	       Lay_WrongCopySrcExit ();
+	       Err_WrongCopySrcExit ();
             break;
          case Brw_ADMI_BRF_USR:
             snprintf (PathOrg,sizeof (PathOrg),"%s/%s",
@@ -8059,7 +8060,7 @@ static void Brw_PasteClipboard (void)
         	      Gbl.FileBrowser.Clipboard.FilFolLnk.Full);
             break;
          default:
-            Lay_WrongFileBrowserExit ();
+            Err_WrongFileBrowserExit ();
             break;
         }
 
@@ -8119,7 +8120,7 @@ static void Brw_PasteClipboard (void)
       Brw_InsFoldersInPathAndUpdOtherFoldersInExpandedFolders (Gbl.FileBrowser.FilFolLnk.Full);
      }
    else
-      Lay_ShowErrorAndExit (Txt_You_can_not_paste_file_or_folder_here);	// It's difficult, but not impossible that a user sees this message
+      Err_ShowErrorAndExit (Txt_You_can_not_paste_file_or_folder_here);	// It's difficult, but not impossible that a user sees this message
   }
 
 /*****************************************************************************/
@@ -8185,7 +8186,7 @@ static bool Brw_PasteTreeIntoFolder (unsigned LevelOrg,
    /***** Is it a file or a folder? *****/
    FileType = Brw_IS_UNKNOWN;
    if (lstat (PathOrg,&FileStatus))	// On success ==> 0 is returned
-      Lay_ShowErrorAndExit ("Can not get information about a file or folder.");
+      Err_ShowErrorAndExit ("Can not get information about a file or folder.");
    else if (S_ISDIR (FileStatus.st_mode))	// It's a directory
       FileType = Brw_IS_FOLDER;
    else if (S_ISREG (FileStatus.st_mode))	// It's a regular file
@@ -8233,7 +8234,7 @@ static bool Brw_PasteTreeIntoFolder (unsigned LevelOrg,
 		           FileNameToShow);
 	    break;
 	 default:
-            Lay_ShowErrorAndExit ("Can not paste unknown file type.");
+            Err_ShowErrorAndExit ("Can not paste unknown file type.");
         }
       CopyIsGoingSuccessful = false;
      }
@@ -8326,7 +8327,7 @@ static bool Brw_PasteTreeIntoFolder (unsigned LevelOrg,
 		 {
 		  /* Create directory */
 		  if (mkdir (PathDstWithFile,(mode_t) 0xFFF) != 0)
-		     Lay_ShowErrorAndExit ("Can not create folder.");
+		     Err_ShowErrorAndExit ("Can not create folder.");
 
 		  /* Add entry to the table of files/folders */
 		  Brw_AddPathToDB (Gbl.Usrs.Me.UsrDat.UsrCod,FileType,
@@ -8358,7 +8359,7 @@ static bool Brw_PasteTreeIntoFolder (unsigned LevelOrg,
 	    free (FileList);
 	   }
 	 else
-	    Lay_ShowErrorAndExit ("Error while scanning directory.");
+	    Err_ShowErrorAndExit ("Error while scanning directory.");
 
 	 if (CopyIsGoingSuccessful &&
 	     LevelOrg != 0)	// When copying all files inside root folder,
@@ -8417,7 +8418,7 @@ void Brw_ShowFormFileBrowser (void)
      }
    else
      {
-      Lay_ShowErrorAndExit (Txt_You_can_not_create_folders_files_or_links_here);	// It's difficult, but not impossible that a user sees this message
+      Err_ShowErrorAndExit (Txt_You_can_not_create_folders_files_or_links_here);	// It's difficult, but not impossible that a user sees this message
 
       /***** Show again file browser *****/
       Brw_ShowAgainFileBrowserOrWorks ();
@@ -8636,7 +8637,7 @@ static void Brw_PutFormToCreateALink (const char *FileNameToShow)
 
    /* Label */
    if (asprintf (&Label,"%s&nbsp;(%s):&nbsp;",Txt_Save_as,Txt_optional) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    Frm_LabelColumn ("RT","NewLinkName",Label);
    free (Label);
 
@@ -8685,7 +8686,7 @@ void Brw_RecFolderFileBrowser (void)
 		   Gbl.FileBrowser.FilFolLnk.Full);
 
          if (strlen (Path) + 1 + strlen (Gbl.FileBrowser.NewFilFolLnkName) > PATH_MAX)
-	    Lay_ShowErrorAndExit ("Path is too long.");
+	    Err_ShowErrorAndExit ("Path is too long.");
          Str_Concat (Path,"/",sizeof (Path) - 1);
          Str_Concat (Path,Gbl.FileBrowser.NewFilFolLnkName,sizeof (Path) - 1);
 
@@ -8739,10 +8740,10 @@ void Brw_RecFolderFileBrowser (void)
 		   	         Gbl.FileBrowser.NewFilFolLnkName);
 	          break;
 	       case EACCES:
-	          Lay_ShowErrorAndExit ("Write forbidden.");
+	          Err_ShowErrorAndExit ("Write forbidden.");
 	          break;
 	       default:
-	          Lay_ShowErrorAndExit ("Can not create folder.");
+	          Err_ShowErrorAndExit ("Can not create folder.");
 	          break;
 	      }
 	   }
@@ -8751,7 +8752,7 @@ void Brw_RecFolderFileBrowser (void)
          Ale_ShowAlerts (NULL);
      }
    else
-      Lay_ShowErrorAndExit (Txt_You_can_not_create_folders_here);	// It's difficult, but not impossible that a user sees this message
+      Err_ShowErrorAndExit (Txt_You_can_not_create_folders_here);	// It's difficult, but not impossible that a user sees this message
 
    /***** Show again the file browser *****/
    Brw_ShowAgainFileBrowserOrWorks ();
@@ -8792,7 +8793,7 @@ void Brw_RenFolderFileBrowser (void)
             if (strlen (Gbl.FileBrowser.Priv.PathAboveRootFolder) + 1 +
                 strlen (Gbl.FileBrowser.FilFolLnk.Path) + 1 +
                 strlen (Gbl.FileBrowser.NewFilFolLnkName) > PATH_MAX)
-	       Lay_ShowErrorAndExit ("Path is too long.");
+	       Err_ShowErrorAndExit ("Path is too long.");
             snprintf (NewPathInTree,sizeof (NewPathInTree),"%s/%s",
         	      Gbl.FileBrowser.FilFolLnk.Path,
 		      Gbl.FileBrowser.NewFilFolLnkName);
@@ -8814,10 +8815,10 @@ void Brw_RenFolderFileBrowser (void)
 			            Gbl.FileBrowser.FilFolLnk.Name,Gbl.FileBrowser.NewFilFolLnkName);
 	             break;
 	          case EACCES:
-	             Lay_ShowErrorAndExit ("Write forbidden.");
+	             Err_ShowErrorAndExit ("Write forbidden.");
 	             break;
 	          default:
-	             Lay_ShowErrorAndExit ("Can not rename folder.");
+	             Err_ShowErrorAndExit ("Can not rename folder.");
 	             break;
 	         }
 	      }
@@ -8858,7 +8859,7 @@ void Brw_RenFolderFileBrowser (void)
          Ale_ShowAlerts (NULL);
      }
    else
-      Lay_ShowErrorAndExit (Txt_You_can_not_rename_this_folder);
+      Err_ShowErrorAndExit (Txt_You_can_not_rename_this_folder);
 
    /***** Show again file browser *****/
    Brw_ShowAgainFileBrowserOrWorks ();
@@ -8968,7 +8969,7 @@ static bool Brw_RcvFileInFileBrw (Brw_UploadType_t UploadType)
                if (strlen (Path) + 1 +
         	   strlen (Gbl.FileBrowser.NewFilFolLnkName) +
 		   strlen (".tmp") > PATH_MAX)
-	          Lay_ShowErrorAndExit ("Path is too long.");
+	          Err_ShowErrorAndExit ("Path is too long.");
                Str_Concat (Path,"/",sizeof (Path) - 1);
                Str_Concat (Path,Gbl.FileBrowser.NewFilFolLnkName,sizeof (Path) - 1);
 
@@ -9165,7 +9166,7 @@ void Brw_RecLinkFileBrowser (void)
 		      Gbl.FileBrowser.Priv.PathAboveRootFolder,
 		      Gbl.FileBrowser.FilFolLnk.Full);
 	    if (strlen (Path) + 1 + strlen (FileName) + strlen (".url") > PATH_MAX)
-	       Lay_ShowErrorAndExit ("Path is too long.");
+	       Err_ShowErrorAndExit ("Path is too long.");
 	    Str_Concat (Path,"/",sizeof (Path) - 1);
 	    Str_Concat (Path,FileName,sizeof (Path) - 1);
 	    Str_Concat (Path,".url",sizeof (Path) - 1);
@@ -9258,7 +9259,7 @@ void Brw_RecLinkFileBrowser (void)
 	 Ale_ShowAlert (Ale_WARNING,Txt_UPLOAD_FILE_Invalid_link);
      }
    else
-      Lay_ShowErrorAndExit (Txt_You_can_not_create_links_here);	// It's difficult, but not impossible that a user sees this message
+      Err_ShowErrorAndExit (Txt_You_can_not_create_links_here);	// It's difficult, but not impossible that a user sees this message
 
    /***** Show again the file browser *****/
    Brw_ShowAgainFileBrowserOrWorks ();
@@ -10345,7 +10346,7 @@ void Brw_ChgFileMetadata (void)
 	}
       else
 	 /***** Write error message and exit *****/
-	 Lay_NoPermissionExit ();
+	 Err_NoPermissionExit ();
      }
 
    /***** Show again the file browser *****/
@@ -11876,7 +11877,7 @@ void Brw_GetSummaryAndContentOfFile (char SummaryStr[Ntf_MAX_BYTES_SUMMARY + 1],
 		    Txt_Uploaded_by,
 		    FileHasPublisher ? PublisherUsrDat.FullName :
 				       Txt_ROLES_SINGUL_Abc[Rol_UNK][Usr_SEX_UNKNOWN]) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
 
       /* Free memory used for publisher's data */
       if (FileMetadata.PublisherUsrCod > 0)
@@ -12380,7 +12381,7 @@ static void Brw_ScanDirRemovingOldFiles (unsigned Level,
    // Folder st_mtime must be saved before remove files inside it
    // because st_mtime is updated by the deletion
    if (lstat (Path,&FolderStatus))	// On success ==> 0 is returned
-      Lay_ShowErrorAndExit ("Can not get information about a file or folder.");
+      Err_ShowErrorAndExit ("Can not get information about a file or folder.");
    /***** Scan directory *****/
    else if ((NumFiles = scandir (Path,&FileList,NULL,alphasort)) >= 0)	// No error
      {
@@ -12400,7 +12401,7 @@ static void Brw_ScanDirRemovingOldFiles (unsigned Level,
 
 	    /***** Get file or folder status *****/
 	    if (lstat (PathFileRel,&FileStatus))	// On success ==> 0 is returned
-	       Lay_ShowErrorAndExit ("Can not get information about a file or folder.");
+	       Err_ShowErrorAndExit ("Can not get information about a file or folder.");
 	    else if (S_ISDIR (FileStatus.st_mode))				// It's a folder
 	       /* Scan subtree starting at this this directory recursively */
 	       Brw_ScanDirRemovingOldFiles (Level + 1,PathFileRel,
@@ -12440,7 +12441,7 @@ static void Brw_ScanDirRemovingOldFiles (unsigned Level,
 	       free (FileList);
 	      }
 	    else
-	       Lay_ShowErrorAndExit ("Error while scanning directory.");
+	       Err_ShowErrorAndExit ("Error while scanning directory.");
 	   }
 
 	 if (NumFiles <= 2 &&					// It's an empty folder
@@ -12448,7 +12449,7 @@ static void Brw_ScanDirRemovingOldFiles (unsigned Level,
 	   {
 	    /* Remove folder from disk and database */
 	    if (Brw_RemoveFolderFromDiskAndDB (Path,PathInTree))
-	       Lay_ShowErrorAndExit ("Can not remove folder.");
+	       Err_ShowErrorAndExit ("Can not remove folder.");
 
 	    /* Update number of files/links removed */
 	    (Removed->NumFolds)++;
@@ -12456,7 +12457,7 @@ static void Brw_ScanDirRemovingOldFiles (unsigned Level,
 	}
      }
    else
-      Lay_ShowErrorAndExit ("Error while scanning directory.");
+      Err_ShowErrorAndExit ("Error while scanning directory.");
   }
 
 /*****************************************************************************/
@@ -12468,7 +12469,7 @@ static void Brw_RemoveFileFromDiskAndDB (const char Path[PATH_MAX + 1],
   {
    /***** Remove file from disk *****/
    if (unlink (Path))
-      Lay_ShowErrorAndExit ("Can not remove file / link.");
+      Err_ShowErrorAndExit ("Can not remove file / link.");
 
    /***** If a file is removed,
           it is necessary to remove it from the database *****/
diff --git a/swad_follow.c b/swad_follow.c
index 0f5c9e67..90968204 100644
--- a/swad_follow.c
+++ b/swad_follow.c
@@ -30,6 +30,7 @@
 
 #include "swad_box.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_figure.h"
 #include "swad_follow.h"
 #include "swad_form.h"
@@ -1496,7 +1497,7 @@ void Fol_GetAndShowRankingFollowers (void)
 			 Gbl.Hierarchy.Crs.CrsCod);
          break;
       default:
-         Lay_WrongScopeExit ();
+         Err_WrongScopeExit ();
          break;
      }
 
diff --git a/swad_form.c b/swad_form.c
index a44fd6f0..45faed38 100644
--- a/swad_form.c
+++ b/swad_form.c
@@ -29,6 +29,7 @@
 #include <stdio.h>		// For asprintf
 #include <stdlib.h>		// For free
 
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_HTML.h"
@@ -271,7 +272,7 @@ void Frm_SetAnchorStr (long Cod,char **Anchor)
      {
       if (asprintf (Anchor,"cod_%ld",
 		    Cod) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
      }
    else
       *Anchor = NULL;
diff --git a/swad_forum.c b/swad_forum.c
index a5bbd62d..6bca2e32 100644
--- a/swad_forum.c
+++ b/swad_forum.c
@@ -37,6 +37,7 @@
 #include "swad_box.h"
 #include "swad_config.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_figure.h"
 #include "swad_form.h"
 #include "swad_forum.h"
@@ -490,7 +491,7 @@ void For_DisablePost (void)
       For_ShowPostsOfAThread (&Forums,Ale_SUCCESS,Txt_FORUM_Post_banned);
      }
    else
-      Lay_WrongPostExit ();
+      Err_WrongPostExit ();
   }
 
 /*****************************************************************************/
@@ -651,9 +652,9 @@ static unsigned For_NumPstsInThrWithPstCod (long PstCod,long *ThrCod)
      {
       row = mysql_fetch_row (mysql_res);
       if (sscanf (row[0],"%u",&NumPsts) != 1)
-	 Lay_ShowErrorAndExit ("Error when getting number of posts in a thread.");
+	 Err_ShowErrorAndExit ("Error when getting number of posts in a thread.");
       if (sscanf (row[1],"%ld",ThrCod) != 1)
-	 Lay_ShowErrorAndExit ("Error when getting number of posts in a thread.");
+	 Err_ShowErrorAndExit ("Error when getting number of posts in a thread.");
      }
    DB_FreeMySQLResult (&mysql_res);
 
@@ -842,7 +843,7 @@ static long For_GetLastPstCod (long ThrCod)
 				    " LIMIT 1",
 				    ThrCod);
    if (LastPstCod <= 0)
-      Lay_ShowErrorAndExit ("Error when getting the most recent post of a thread of a forum.");
+      Err_ShowErrorAndExit ("Error when getting the most recent post of a thread of a forum.");
 
    return LastPstCod;
   }
@@ -1123,7 +1124,7 @@ static void For_ShowPostsOfAThread (struct For_Forums *Forums,
          row = mysql_fetch_row (mysql_res);
 
          if (sscanf (row[0],"%ld",&Forums->PstCod) != 1)
-            Lay_WrongPostExit ();
+            Err_WrongPostExit ();
 
          CreatTimeUTC = Dat_GetUNIXTimeFromStr (row[1]);
 
@@ -1385,7 +1386,7 @@ static void For_GetPstData (long PstCod,long *UsrCod,time_t *CreatTimeUTC,
 			      " FROM for_posts"
 			     " WHERE PstCod=%ld",
 			     PstCod) != 1)
-      Lay_WrongPostExit ();
+      Err_WrongPostExit ();
 
    /***** Get number of rows *****/
    row = mysql_fetch_row (mysql_res);
@@ -1442,7 +1443,7 @@ void For_GetSummaryAndContentForumPst (char SummaryStr[Ntf_MAX_BYTES_SUMMARY + 1
 	 Length = strlen (row[1]);
 
 	 if ((*ContentStr = malloc (Length + 1)) == NULL)
-            Lay_NotEnoughMemoryExit ();
+            Err_NotEnoughMemoryExit ();
 
 	 if (Length)
 	    Str_Copy (*ContentStr,row[1],Length);
@@ -2215,13 +2216,13 @@ void For_SetForumName (const struct For_Forum *Forum,
       case For_FORUM_INSTIT_USRS:
 	 Hie.Ins.InsCod = Forum->Location;
 	 if (!Ins_GetDataOfInstitutionByCod (&Hie.Ins))
-	    Lay_WrongInstitExit ();
+	    Err_WrongInstitExit ();
          Str_Copy (ForumName,Hie.Ins.ShrtName,For_MAX_BYTES_FORUM_NAME);
          break;
       case For_FORUM_INSTIT_TCHS:
 	 Hie.Ins.InsCod = Forum->Location;
 	 if (!Ins_GetDataOfInstitutionByCod (&Hie.Ins))
-	    Lay_WrongInstitExit ();
+	    Err_WrongInstitExit ();
          snprintf (ForumName,For_MAX_BYTES_FORUM_NAME + 1,"%s%s",
                    Hie.Ins.ShrtName,
                    UseHTMLEntities ? Txt_only_teachers :
@@ -2230,13 +2231,13 @@ void For_SetForumName (const struct For_Forum *Forum,
       case For_FORUM_CENTER_USRS:
 	 Hie.Ctr.CtrCod = Forum->Location;
 	 if (!Ctr_GetDataOfCenterByCod (&Hie.Ctr))
-	    Lay_WrongCenterExit ();
+	    Err_WrongCenterExit ();
          Str_Copy (ForumName,Hie.Ctr.ShrtName,For_MAX_BYTES_FORUM_NAME);
          break;
       case For_FORUM_CENTER_TCHS:
 	 Hie.Ctr.CtrCod = Forum->Location;
 	 if (!Ctr_GetDataOfCenterByCod (&Hie.Ctr))
-	    Lay_WrongCenterExit ();
+	    Err_WrongCenterExit ();
          snprintf (ForumName,For_MAX_BYTES_FORUM_NAME + 1,"%s%s",
                    Hie.Ctr.ShrtName,
                    UseHTMLEntities ? Txt_only_teachers :
@@ -2245,13 +2246,13 @@ void For_SetForumName (const struct For_Forum *Forum,
       case For_FORUM_DEGREE_USRS:
 	 Hie.Deg.DegCod = Forum->Location;
 	 if (!Deg_GetDataOfDegreeByCod (&Hie.Deg))
-	    Lay_WrongDegreeExit ();
+	    Err_WrongDegreeExit ();
          Str_Copy (ForumName,Hie.Deg.ShrtName,For_MAX_BYTES_FORUM_NAME);
          break;
       case For_FORUM_DEGREE_TCHS:
 	 Hie.Deg.DegCod = Forum->Location;
 	 if (!Deg_GetDataOfDegreeByCod (&Hie.Deg))
-	    Lay_WrongDegreeExit ();
+	    Err_WrongDegreeExit ();
          snprintf (ForumName,For_MAX_BYTES_FORUM_NAME + 1,"%s%s",
                    Hie.Deg.ShrtName,
                    UseHTMLEntities ? Txt_only_teachers :
@@ -2260,13 +2261,13 @@ void For_SetForumName (const struct For_Forum *Forum,
       case For_FORUM_COURSE_USRS:
 	 Hie.Crs.CrsCod = Forum->Location;
 	 if (!Crs_GetDataOfCourseByCod (&Hie.Crs))
-	    Lay_WrongCourseExit ();
+	    Err_WrongCourseExit ();
          Str_Copy (ForumName,Hie.Crs.ShrtName,For_MAX_BYTES_FORUM_NAME);
          break;
       case For_FORUM_COURSE_TCHS:
 	 Hie.Crs.CrsCod = Forum->Location;
 	 if (!Crs_GetDataOfCourseByCod (&Hie.Crs))
-	    Lay_WrongCourseExit ();
+	    Err_WrongCourseExit ();
          snprintf (ForumName,For_MAX_BYTES_FORUM_NAME + 1,"%s%s",
                    Hie.Crs.ShrtName,
                    UseHTMLEntities ? Txt_only_teachers :
@@ -2512,7 +2513,7 @@ static void For_ShowForumThreadsHighlightingOneThread (struct For_Forums *Forums
         NumThr++, NumThrInScreen++)
       /* Get thread code(row[0]) */
       if ((ThrCods[NumThrInScreen] = DB_GetNextCode (mysql_res)) < 0)
-         Lay_ShowErrorAndExit ("Error when getting thread of a forum.");
+         Err_ShowErrorAndExit ("Error when getting thread of a forum.");
 
    /***** Free structure that stores the query result *****/
    DB_FreeMySQLResult (&mysql_res);
@@ -3452,13 +3453,13 @@ unsigned For_GetNumTotalPstsInForumsOfType (For_ForumType_t ForumType,
 
    /* Get number of posts (row[0]) */
    if (sscanf (row[0],"%u",&NumPosts) != 1)
-      Lay_ShowErrorAndExit ("Error when getting the total number of forums of a type.");
+      Err_ShowErrorAndExit ("Error when getting the total number of forums of a type.");
 
    /* Get number of users notified (row[1]) */
    if (row[1])
      {
       if (sscanf (row[1],"%u",NumUsrsToBeNotifiedByEMail) != 1)
-         Lay_ShowErrorAndExit ("Error when getting the total number of forums of a type.");
+         Err_ShowErrorAndExit ("Error when getting the total number of forums of a type.");
      }
    else
       *NumUsrsToBeNotifiedByEMail = 0;
@@ -3605,7 +3606,7 @@ static void For_ListForumThrs (struct For_Forums *Forums,
 	       TimeUTC = Thr.WriteTime[Order];
 	       UniqueId++;
 	       if (asprintf (&Id,"thr_date_%u",UniqueId) < 0)
-		  Lay_NotEnoughMemoryExit ();
+		  Err_NotEnoughMemoryExit ();
 	       HTM_TD_Begin ("id=\"%s\" class=\"%s LT %s\"",Id,Style,BgColor);
 		  Dat_WriteLocalDateHMSFromUTC (Id,TimeUTC,
 						Gbl.Prefs.DateFormat,Dat_SEPARATOR_BREAK,
@@ -3677,7 +3678,7 @@ static void For_GetThreadData (struct For_Thread *Thr)
 			 " AND for_threads.FirstPstCod=m0.PstCod"
 			 " AND for_threads.LastPstCod=m1.PstCod",
 		       Thr->ThrCod) != 1)
-      Lay_ShowErrorAndExit ("Error when getting data of a thread of a forum.");
+      Err_ShowErrorAndExit ("Error when getting data of a thread of a forum.");
    row = mysql_fetch_row (mysql_res);
 
    /***** Get the code of the first post in this thread (row[0]) *****/
@@ -3689,9 +3690,9 @@ static void For_GetThreadData (struct For_Thread *Thr)
    /***** Get the code of the first message (row[0])
           and the last message (row[1]) in this thread *****/
    if (sscanf (row[0],"%ld",&(Thr->PstCod[Dat_START_TIME])) != 1)
-      Lay_WrongPostExit ();
+      Err_WrongPostExit ();
    if (sscanf (row[1],"%ld",&(Thr->PstCod[Dat_END_TIME])) != 1)
-      Lay_WrongPostExit ();
+      Err_WrongPostExit ();
 
    /***** Get the author of the first post in this thread (row[2]) *****/
    Thr->UsrCod[Dat_START_TIME] = Str_ConvertStrCodToLongCod (row[2]);
@@ -4005,7 +4006,7 @@ static void For_RestrictAccess (const struct For_Forums *Forums)
 	 break;
      }
    if (!ICanSeeForum)
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
   }
 
 /*****************************************************************************/
@@ -4266,16 +4267,16 @@ void For_RemovePost (void)
    /***** Check if I can remove the post *****/
    /* Check if the message really exists, if it has not been removed */
    if (!For_GetIfForumPstExists (Forums.PstCod))
-      Lay_WrongPostExit ();
+      Err_WrongPostExit ();
 
    /* Check if I am the author of the message */
    ItsMe = Usr_ItsMe (UsrDat.UsrCod);
    if (!ItsMe)
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /* Check if the message is the last message in the thread */
    if (Forums.PstCod != For_GetLastPstCod (Forums.Thread.Current))
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Remove the post *****/
    ThreadDeleted = For_RemoveForumPst (Forums.PstCod,Media.MedCod);
@@ -4411,7 +4412,7 @@ void For_RemoveThread (void)
 	 For_ShowForumThreadsHighlightingOneThread (&Forums,Ale_SUCCESS,Txt_Thread_removed);
      }
    else
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
   }
 
 /*****************************************************************************/
@@ -4626,7 +4627,7 @@ static void For_MoveThrToCurrentForum (const struct For_Forums *Forums)
 		         Forums->Thread.Current);
          break;
       default:
-	 Lay_WrongForumExit ();
+	 Err_WrongForumExit ();
 	 break;
      }
   }
diff --git a/swad_game.c b/swad_game.c
index 4d680c82..d837a7fb 100644
--- a/swad_game.c
+++ b/swad_game.c
@@ -34,6 +34,7 @@
 #include <string.h>		// For string functions
 
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_figure.h"
 #include "swad_form.h"
 #include "swad_game.h"
@@ -469,7 +470,7 @@ void Gam_SeeOneGame (void)
 
    /***** Get parameters *****/
    if ((Game.GamCod = Gam_GetParams (&Games)) <= 0)
-      Lay_WrongGameExit ();
+      Err_WrongGameExit ();
    Gam_GetDataOfGameByCod (&Game);
 
    /***** Show game *****/
@@ -580,7 +581,7 @@ static void Gam_ShowOneGame (struct Gam_Games *Games,
 	StartEndTime++)
      {
       if (asprintf (&Id,"gam_date_%u_%u",(unsigned) StartEndTime,UniqueId) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       Color = Game->NumUnfinishedMchs ? (Game->Hidden ? "DATE_GREEN_LIGHT":
 							"DATE_GREEN") :
 					(Game->Hidden ? "DATE_RED_LIGHT":
@@ -878,7 +879,7 @@ void Gam_GetListGames (struct Gam_Games *Games,Gam_Order_t SelectedOrder)
      {
       case Rol_STD:
          if (asprintf (&HiddenSubQuery," AND gam_games.Hidden='N'") < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 	 break;
       case Rol_NET:
       case Rol_TCH:
@@ -887,10 +888,10 @@ void Gam_GetListGames (struct Gam_Games *Games,Gam_Order_t SelectedOrder)
       case Rol_INS_ADM:
       case Rol_SYS_ADM:
 	 if (asprintf (&HiddenSubQuery,"%s","") < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 	 break;
       default:
-	 Lay_WrongRoleExit ();
+	 Err_WrongRoleExit ();
 	 break;
      }
 
@@ -919,7 +920,7 @@ void Gam_GetListGames (struct Gam_Games *Games,Gam_Order_t SelectedOrder)
       /***** Create list of games *****/
       if ((Games->Lst = malloc ((size_t) Games->Num *
                                 sizeof (*Games->Lst))) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
 
       /***** Get the games codes *****/
       for (NumGame = 0;
@@ -929,7 +930,7 @@ void Gam_GetListGames (struct Gam_Games *Games,Gam_Order_t SelectedOrder)
          /* Get next game code (row[0]) */
          row = mysql_fetch_row (mysql_res);
          if ((Games->Lst[NumGame].GamCod = Str_ConvertStrCodToLongCod (row[0])) <= 0)
-            Lay_WrongGameExit ();
+            Err_WrongGameExit ();
         }
      }
 
@@ -961,7 +962,7 @@ void Gam_GetListSelectedGamCods (struct Gam_Games *Games)
    /***** Allocate memory for list of games selected *****/
    MaxSizeListGamCodsSelected = Games->Num * (Cns_MAX_DECIMAL_DIGITS_LONG + 1);
    if ((Games->GamCodsSelected = malloc (MaxSizeListGamCodsSelected + 1)) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Get parameter multiple with list of games selected *****/
    Par_GetParMultiToText ("GamCod",Games->GamCodsSelected,MaxSizeListGamCodsSelected);
@@ -1154,12 +1155,12 @@ void Gam_AskRemGame (void)
 
    /***** Get parameters *****/
    if ((Game.GamCod = Gam_GetParams (&Games)) <= 0)
-      Lay_WrongGameExit ();
+      Err_WrongGameExit ();
 
    /***** Get data of the game from database *****/
    Gam_GetDataOfGameByCod (&Game);
    if (!Gam_CheckIfICanEditGames ())
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Show question and button to remove game *****/
    Games.GamCod = Game.GamCod;
@@ -1191,12 +1192,12 @@ void Gam_RemoveGame (void)
 
    /***** Get game code *****/
    if ((Game.GamCod = Gam_GetParamGameCod ()) <= 0)
-      Lay_WrongGameExit ();
+      Err_WrongGameExit ();
 
    /***** Get data of the game from database *****/
    Gam_GetDataOfGameByCod (&Game);
    if (!Gam_CheckIfICanEditGames ())
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Remove game from all tables *****/
    Gam_RemoveGameFromAllTables (Game.GamCod);
@@ -1273,12 +1274,12 @@ void Gam_HideGame (void)
 
    /***** Get parameters *****/
    if ((Game.GamCod = Gam_GetParams (&Games)) <= 0)
-      Lay_WrongGameExit ();
+      Err_WrongGameExit ();
 
    /***** Get data of the game from database *****/
    Gam_GetDataOfGameByCod (&Game);
    if (!Gam_CheckIfICanEditGames ())
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Hide game *****/
    DB_QueryUPDATE ("can not hide game",
@@ -1308,12 +1309,12 @@ void Gam_UnhideGame (void)
 
    /***** Get parameters *****/
    if ((Game.GamCod = Gam_GetParams (&Games)) <= 0)
-      Lay_WrongGameExit ();
+      Err_WrongGameExit ();
 
    /***** Get data of the game from database *****/
    Gam_GetDataOfGameByCod (&Game);
    if (!Gam_CheckIfICanEditGames ())
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Show game *****/
    DB_QueryUPDATE ("can not show game",
@@ -1362,11 +1363,11 @@ void Gam_ListGame (void)
 
    /***** Check if I can list game questions *****/
    if (!Gam_CheckIfICanListGameQuestions ())
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Get parameters *****/
    if ((Game.GamCod = Gam_GetParams (&Games)) <= 0)
-      Lay_WrongGameExit ();
+      Err_WrongGameExit ();
 
    /***** Get game data *****/
    Gam_GetDataOfGameByCod (&Game);
@@ -1397,7 +1398,7 @@ void Gam_RequestCreatOrEditGame (void)
 
    /***** Check if I can edit games *****/
    if (!Gam_CheckIfICanEditGames ())
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Get parameters *****/
    ItsANewGame = ((Game.GamCod = Gam_GetParams (&Games)) <= 0);
@@ -1555,7 +1556,7 @@ void Gam_ReceiveFormGame (void)
 
    /***** Check if I can edit games *****/
    if (!Gam_CheckIfICanEditGames ())
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Get parameters *****/
    ItsANewGame = ((Game.GamCod = Gam_GetParams (&Games)) <= 0);
@@ -1594,7 +1595,7 @@ void Gam_ReceiveFormGame (void)
 	}
      }
    else
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
   }
 
 static void Gam_ReceiveGameFieldsFromForm (struct Gam_Game *Game,
@@ -1738,12 +1739,12 @@ void Gam_ReqSelectQstsToAddToGame (void)
 
    /***** Get parameters *****/
    if ((Game.GamCod = Gam_GetParams (&Games)) <= 0)
-      Lay_WrongGameExit ();
+      Err_WrongGameExit ();
    Gam_GetDataOfGameByCod (&Game);
 
    /***** Check if game has matches *****/
    if (!Gam_CheckIfEditable (&Game))
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Show form to create a new question in this game *****/
    Games.GamCod = Game.GamCod;
@@ -1772,12 +1773,12 @@ void Gam_ListQstsToAddToGame (void)
 
    /***** Get parameters *****/
    if ((Game.GamCod = Gam_GetParams (&Games)) <= 0)
-      Lay_WrongGameExit ();
+      Err_WrongGameExit ();
    Gam_GetDataOfGameByCod (&Game);
 
    /***** Check if game has matches *****/
    if (!Gam_CheckIfEditable (&Game))
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** List several test questions for selection *****/
    Games.GamCod = Game.GamCod;
@@ -1802,7 +1803,7 @@ unsigned Gam_GetParamQstInd (void)
    long QstInd;
 
    if ((QstInd = Par_GetParToLong ("QstInd")) <= 0)
-      Lay_WrongQuestionIndexExit ();
+      Err_WrongQuestionIndexExit ();
 
    return (unsigned) QstInd;
   }
@@ -1858,7 +1859,7 @@ long Gam_GetQstCodFromQstInd (long GamCod,unsigned QstInd)
 				GamCod,
 				QstInd);
    if (QstCod <= 0)
-      Lay_WrongQuestionIndexExit ();
+      Err_WrongQuestionIndexExit ();
 
    return QstCod;
   }
@@ -2169,12 +2170,12 @@ void Gam_AddQstsToGame (void)
 
    /***** Get parameters *****/
    if ((Game.GamCod = Gam_GetParams (&Games)) <= 0)
-      Lay_WrongGameExit ();
+      Err_WrongGameExit ();
    Gam_GetDataOfGameByCod (&Game);
 
    /***** Check if game has matches *****/
    if (!Gam_CheckIfEditable (&Game))
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Get selected questions *****/
    /* Allocate space for selected question codes */
@@ -2195,7 +2196,7 @@ void Gam_AddQstsToGame (void)
 	 /* Get next code */
 	 Par_GetNextStrUntilSeparParamMult (&Ptr,LongStr,Cns_MAX_DECIMAL_DIGITS_LONG);
 	 if (sscanf (LongStr,"%ld",&QstCod) != 1)
-	    Lay_WrongQuestionExit ();
+	    Err_WrongQuestionExit ();
 
 	 /* Check if question is already present in game */
 	 if (Gam_GetQstIndFromQstCod (Game.GamCod,QstCod) == 0)	// This question is not yet in this game
@@ -2244,7 +2245,7 @@ static void Gam_AllocateListSelectedQuestions (struct Gam_Games *Games)
    if (!Games->ListQuestions)
      {
       if ((Games->ListQuestions = malloc (Gam_MAX_BYTES_LIST_SELECTED_QUESTIONS + 1)) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
       Games->ListQuestions[0] = '\0';
      }
   }
@@ -2282,12 +2283,12 @@ void Gam_RequestRemoveQstFromGame (void)
 
    /***** Get parameters *****/
    if ((Game.GamCod = Gam_GetParams (&Games)) <= 0)
-      Lay_WrongGameExit ();
+      Err_WrongGameExit ();
    Gam_GetDataOfGameByCod (&Game);
 
    /***** Check if game has matches *****/
    if (!Gam_CheckIfEditable (&Game))
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Get question index *****/
    QstInd = Gam_GetParamQstInd ();
@@ -2326,12 +2327,12 @@ void Gam_RemoveQstFromGame (void)
 
    /***** Get parameters *****/
    if ((Game.GamCod = Gam_GetParams (&Games)) <= 0)
-      Lay_WrongGameExit ();
+      Err_WrongGameExit ();
    Gam_GetDataOfGameByCod (&Game);
 
    /***** Check if game has matches *****/
    if (!Gam_CheckIfEditable (&Game))
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Get question index *****/
    QstInd = Gam_GetParamQstInd ();
@@ -2348,7 +2349,7 @@ void Gam_RemoveQstFromGame (void)
 		   Game.GamCod,
 		   QstInd);
    if (!mysql_affected_rows (&Gbl.mysql))
-      Lay_WrongQuestionExit ();
+      Err_WrongQuestionExit ();
 
    /* Change index of questions greater than this */
    DB_QueryUPDATE ("can not update indexes of questions in table of answers",
@@ -2397,12 +2398,12 @@ void Gam_MoveUpQst (void)
 
    /***** Get parameters *****/
    if ((Game.GamCod = Gam_GetParams (&Games)) <= 0)
-      Lay_WrongGameExit ();
+      Err_WrongGameExit ();
    Gam_GetDataOfGameByCod (&Game);
 
    /***** Check if game has matches *****/
    if (!Gam_CheckIfEditable (&Game))
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Get question index *****/
    QstIndBottom = Gam_GetParamQstInd ();
@@ -2413,7 +2414,7 @@ void Gam_MoveUpQst (void)
       /* Indexes of questions to be exchanged */
       QstIndTop = Gam_GetPrevQuestionIndexInGame (Game.GamCod,QstIndBottom);
       if (!QstIndTop)
-	 Lay_WrongQuestionIndexExit ();
+	 Err_WrongQuestionIndexExit ();
 
       /* Exchange questions */
       Gam_ExchangeQuestions (Game.GamCod,QstIndTop,QstIndBottom);
@@ -2448,12 +2449,12 @@ void Gam_MoveDownQst (void)
 
    /***** Get parameters *****/
    if ((Game.GamCod = Gam_GetParams (&Games)) <= 0)
-      Lay_WrongGameExit ();
+      Err_WrongGameExit ();
    Gam_GetDataOfGameByCod (&Game);
 
    /***** Check if game has matches *****/
    if (!Gam_CheckIfEditable (&Game))
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Get question index *****/
    QstIndTop = Gam_GetParamQstInd ();
@@ -2467,7 +2468,7 @@ void Gam_MoveDownQst (void)
       /* Indexes of questions to be exchanged */
       QstIndBottom = Gam_GetNextQuestionIndexInGame (Game.GamCod,QstIndTop);
       if (!QstIndBottom)
-	 Lay_WrongQuestionIndexExit ();
+	 Err_WrongQuestionIndexExit ();
 
       /* Exchange questions */
       Gam_ExchangeQuestions (Game.GamCod,QstIndTop,QstIndBottom);
@@ -2598,7 +2599,7 @@ void Gam_RequestNewMatch (void)
 
    /***** Get parameters *****/
    if ((Game.GamCod = Gam_GetParams (&Games)) <= 0)
-      Lay_WrongGameExit ();
+      Err_WrongGameExit ();
    Gam_GetDataOfGameByCod (&Game);
 
    /***** Show game *****/
@@ -2845,7 +2846,7 @@ double Gam_GetNumQstsPerCrsGame (Hie_Lvl_Level_t Scope)
 					      " GROUP BY gam_questions.GamCod) AS NumQstsTable",
 				      Gbl.Hierarchy.Crs.CrsCod);
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 return 0.0;	// Not reached
      }
   }
@@ -2896,7 +2897,7 @@ void Gam_GetScoreRange (long GamCod,double *MinScore,double *MaxScore)
 		  " GROUP BY tst_answers.QstCod",
 		  GamCod);
    if (NumAnswers < 2)
-      Lay_WrongAnswerExit ();
+      Err_WrongAnswerExit ();
 
    /***** Set minimum and maximum scores *****/
    *MinScore = *MaxScore = 0.0;
diff --git a/swad_group.c b/swad_group.c
index 40b4b03f..290d9380 100644
--- a/swad_group.c
+++ b/swad_group.c
@@ -35,6 +35,7 @@
 #include "swad_attendance.h"
 #include "swad_box.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_exam_session.h"
 #include "swad_form.h"
 #include "swad_game.h"
@@ -503,7 +504,7 @@ void Grp_PutParamsCodGrps (void)
      {
       MaxLengthGrpCods = Gbl.Crs.Grps.LstGrpsSel.NumGrps * (Cns_MAX_DECIMAL_DIGITS_LONG + 1) - 1;
       if ((GrpCods = malloc (MaxLengthGrpCods + 1)) == NULL)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       GrpCods[0] = '\0';
 
       for (NumGrpSel = 0;
@@ -554,7 +555,7 @@ void Grp_GetParCodsSeveralGrpsToShowUsrs (void)
 	 /* Allocate space for list of selected groups */
 	 if ((Gbl.Crs.Grps.LstGrpsSel.GrpCods = calloc (LstGrpsIBelong.NumGrps,
 	                                                sizeof (*Gbl.Crs.Grps.LstGrpsSel.GrpCods))) == NULL)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /* Fill list of selected groups with list of groups I belong to */
 	 for (NumGrp = 0;
@@ -592,7 +593,7 @@ void Grp_GetParCodsSeveralGrps (void)
      {
       /***** Allocate memory for the list of group codes selected *****/
       if ((ParamLstCodGrps = malloc (MaxSizeLstGrpCods + 1)) == NULL)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
 
       /***** Get parameter with list of groups to list *****/
       Par_GetParMultiToText ("GrpCods",ParamLstCodGrps,MaxSizeLstGrpCods);
@@ -611,7 +612,7 @@ void Grp_GetParCodsSeveralGrps (void)
 	    /***** Create a list of groups selected from LstCodGrps *****/
 	    if ((Gbl.Crs.Grps.LstGrpsSel.GrpCods = calloc (Gbl.Crs.Grps.LstGrpsSel.NumGrps,
 	                                                   sizeof (*Gbl.Crs.Grps.LstGrpsSel.GrpCods))) == NULL)
-	       Lay_NotEnoughMemoryExit ();
+	       Err_NotEnoughMemoryExit ();
 	    for (Ptr = ParamLstCodGrps, NumGrp = 0;
 		 *Ptr;
 		 NumGrp++)
@@ -1068,7 +1069,7 @@ static void Grp_ConstructorListGrpAlreadySelec (struct ListGrpsAlreadySelec **Al
    /***** Allocate memory to a list of booleanos that indica if already se ha selected a group of cada type *****/
    if ((*AlreadyExistsGroupOfType = calloc (Gbl.Crs.Grps.GrpTypes.Num,
                                             sizeof (**AlreadyExistsGroupOfType))) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Initialize the list *****/
    for (NumGrpTyp = 0;
@@ -2406,7 +2407,7 @@ static void Grp_WriteGrpHead (struct GroupType *GrpTyp)
      {
       UniqueId++;
       if (asprintf (&Id,"open_time_%u",UniqueId) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       HTM_BR ();
       HTM_TxtColonNBSP (Txt_Opening_of_groups);
       HTM_SPAN_Begin ("id=\"%s\"",Id);
@@ -2829,7 +2830,7 @@ void Grp_GetListGrpTypesInThisCrs (Grp_WhichGroupTypes_t WhichGroupTypes)
       /***** Create a list of group types *****/
       if ((Gbl.Crs.Grps.GrpTypes.LstGrpTypes = calloc (Gbl.Crs.Grps.GrpTypes.Num,
                                                        sizeof (*Gbl.Crs.Grps.GrpTypes.LstGrpTypes))) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
 
       /***** Get group types *****/
       for (NumGrpTyp = 0;
@@ -2841,7 +2842,7 @@ void Grp_GetListGrpTypesInThisCrs (Grp_WhichGroupTypes_t WhichGroupTypes)
 
          /* Get group type code (row[0]) */
          if ((Gbl.Crs.Grps.GrpTypes.LstGrpTypes[NumGrpTyp].GrpTypCod = Str_ConvertStrCodToLongCod (row[0])) <= 0)
-            Lay_WrongGrpTypExit ();
+            Err_WrongGrpTypExit ();
 
          /* Get group type name (row[1]) */
          Str_Copy (Gbl.Crs.Grps.GrpTypes.LstGrpTypes[NumGrpTyp].GrpTypName,row[1],
@@ -2862,7 +2863,7 @@ void Grp_GetListGrpTypesInThisCrs (Grp_WhichGroupTypes_t WhichGroupTypes)
 
          /* Number of groups of this type (row[6]) */
          if (sscanf (row[6],"%u",&Gbl.Crs.Grps.GrpTypes.LstGrpTypes[NumGrpTyp].NumGrps) != 1)
-            Lay_ShowErrorAndExit ("Wrong number of groups of a type.");
+            Err_ShowErrorAndExit ("Wrong number of groups of a type.");
 
          /* Add number of groups to total number of groups */
          Gbl.Crs.Grps.GrpTypes.NumGrpsTotal += Gbl.Crs.Grps.GrpTypes.LstGrpTypes[NumGrpTyp].NumGrps;
@@ -2959,7 +2960,7 @@ void Grp_GetListGrpTypesAndGrpsInThisCrs (Grp_WhichGroupTypes_t WhichGroupTypes)
             /***** Create list with groups of this type *****/
             if ((GrpTyp->LstGrps = calloc ((size_t) GrpTyp->NumGrps,
                                            sizeof (*GrpTyp->LstGrps))) == NULL)
-               Lay_NotEnoughMemoryExit ();
+               Err_NotEnoughMemoryExit ();
 
             /***** Get the groups of this type *****/
             for (NumGrp = 0;
@@ -2973,7 +2974,7 @@ void Grp_GetListGrpTypesAndGrpsInThisCrs (Grp_WhichGroupTypes_t WhichGroupTypes)
 
                /* Get group code (row[0]) */
                if ((Grp->GrpCod = Str_ConvertStrCodToLongCod (row[0])) <= 0)
-                  Lay_WrongGroupExit ();
+                  Err_WrongGroupExit ();
 
                /* Get group name (row[1]) */
                Str_Copy (Grp->GrpName,row[1],sizeof (Grp->GrpName) - 1);
@@ -3123,7 +3124,7 @@ static void Grp_GetDataOfGroupTypeByCod (struct GroupType *GrpTyp)
 		       " WHERE CrsCod=%ld"
 			 " AND GrpTypCod=%ld",
 		       Gbl.Hierarchy.Crs.CrsCod,GrpTyp->GrpTypCod) != 1)
-      Lay_WrongGrpTypExit ();
+      Err_WrongGrpTypExit ();
 
    /***** Get some data of group type *****/
    row = mysql_fetch_row (mysql_res);
@@ -3154,7 +3155,7 @@ static bool Grp_GetMultipleEnrolmentOfAGroupType (long GrpTypCod)
 		        " FROM grp_types"
 		       " WHERE GrpTypCod=%ld",
                        GrpTypCod) != 1)
-      Lay_ShowErrorAndExit ("Error when getting type of enrolment.");
+      Err_ShowErrorAndExit ("Error when getting type of enrolment.");
 
    /***** Get multiple enrolment *****/
    row = mysql_fetch_row (mysql_res);
@@ -3215,11 +3216,11 @@ void Grp_GetDataOfGroupByCod (struct GroupData *GrpDat)
 
 	 /* Get the code of the group type (row[0]) */
 	 if ((GrpDat->GrpTypCod = Str_ConvertStrCodToLongCod (row[0])) <= 0)
-	    Lay_WrongGrpTypExit ();
+	    Err_WrongGrpTypExit ();
 
 	 /* Get the code of the course (row[1]) */
 	 if ((GrpDat->CrsCod = Str_ConvertStrCodToLongCod (row[1])) <= 0)
-	    Lay_WrongCourseExit ();
+	    Err_WrongCourseExit ();
 
 	 /* Get the name of the group type (row[2]) */
 	 Str_Copy (GrpDat->GrpTypName,row[2],sizeof (GrpDat->GrpTypName) - 1);
@@ -3270,7 +3271,7 @@ static long Grp_GetTypeOfGroupOfAGroup (long GrpCod)
 				   " WHERE GrpCod=%ld",
 				   GrpCod);
    if (GrpTypCod <= 0)
-      Lay_WrongGrpTypExit ();
+      Err_WrongGrpTypExit ();
 
    return GrpTypCod;
   }
@@ -3504,14 +3505,14 @@ bool Grp_GetIfAvailableGrpTyp (long GrpTypCod)
      {
       if (asprintf (&SubQueryGrpTypes,"grp_types.GrpTypCod=%ld",
 	            GrpTypCod) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
      }
    else			// all mandatory group types in the current course
      {
       if (asprintf (&SubQueryGrpTypes,"grp_types.CrsCod=%ld"
 	                              " AND grp_types.Mandatory='Y'",
 	            Gbl.Hierarchy.Crs.CrsCod) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
      }
 
    /***** Get the number of types of group in this course
@@ -3644,13 +3645,13 @@ static void Grp_GetLstCodGrpsUsrBelongs (long CrsCod,long GrpTypCod,
       /***** Create a list of groups the user belongs to *****/
       if ((LstGrps->GrpCods = calloc (LstGrps->NumGrps,
                                       sizeof (*LstGrps->GrpCods))) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
       for (NumGrp = 0;
 	   NumGrp < LstGrps->NumGrps;
 	   NumGrp++)
          /* Get the code of group (row[0]) */
          if ((LstGrps->GrpCods[NumGrp] = DB_GetNextCode (mysql_res)) <= 0)
-            Lay_WrongGroupExit ();
+            Err_WrongGroupExit ();
      }
 
    /***** Free structure that stores the query result *****/
@@ -3689,13 +3690,13 @@ void Grp_GetLstCodGrpsWithFileZonesIBelong (struct ListCodGrps *LstGrps)
       /***** Create a list of groups I belong to *****/
       if ((LstGrps->GrpCods = calloc (LstGrps->NumGrps,
                                       sizeof (*LstGrps->GrpCods))) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
       for (NumGrp = 0;
 	   NumGrp < LstGrps->NumGrps;
 	   NumGrp++)
          /* Get the code of group */
          if ((LstGrps->GrpCods[NumGrp] = DB_GetNextCode (mysql_res)) <= 0)
-            Lay_WrongGroupExit ();
+            Err_WrongGroupExit ();
      }
 
    /***** Free structure that stores the query result *****/
@@ -3992,7 +3993,7 @@ void Grp_ReqRemGroupType (void)
 
    /***** Get the code of the group type *****/
    if ((Gbl.Crs.Grps.GrpTyp.GrpTypCod = Grp_GetParamGrpTypCod ()) <= 0)
-      Lay_WrongGrpTypExit ();
+      Err_WrongGrpTypExit ();
 
    /***** Check if this group type has groups *****/
    if ((NumGrps = Grp_CountNumGrpsInThisCrsOfType (Gbl.Crs.Grps.GrpTyp.GrpTypCod)))	// Group type has groups ==> Ask for confirmation
@@ -4009,7 +4010,7 @@ void Grp_ReqRemGroup (void)
   {
    /***** Get group code *****/
    if ((Gbl.Crs.Grps.GrpCod = Grp_GetParamGrpCod ()) <= 0)
-      Lay_WrongGroupExit ();
+      Err_WrongGroupExit ();
 
    /***** Confirm removing *****/
    Grp_AskConfirmRemGrp ();
@@ -4106,7 +4107,7 @@ void Grp_RemoveGroupType (void)
   {
    /***** Get param with code of group type *****/
    if ((Gbl.Crs.Grps.GrpTyp.GrpTypCod = Grp_GetParamGrpTypCod ()) <= 0)
-      Lay_WrongGrpTypExit ();
+      Err_WrongGrpTypExit ();
 
    /***** Remove group type and its groups *****/
    Grp_RemoveGroupTypeCompletely ();
@@ -4120,7 +4121,7 @@ void Grp_RemoveGroup (void)
   {
    /***** Get param with group code *****/
    if ((Gbl.Crs.Grps.GrpCod = Grp_GetParamGrpCod ()) <= 0)
-      Lay_WrongGroupExit ();
+      Err_WrongGroupExit ();
 
    /***** Remove group *****/
    Grp_RemoveGroupCompletely ();
@@ -4262,7 +4263,7 @@ void Grp_OpenGroup (void)
 
    /***** Get group code *****/
    if ((Gbl.Crs.Grps.GrpCod = Grp_GetParamGrpCod ()) <= 0)
-      Lay_WrongGroupExit ();
+      Err_WrongGroupExit ();
 
    /***** Get group data from database *****/
    GrpDat.GrpCod = Gbl.Crs.Grps.GrpCod;
@@ -4297,7 +4298,7 @@ void Grp_CloseGroup (void)
 
    /***** Get group code *****/
    if ((Gbl.Crs.Grps.GrpCod = Grp_GetParamGrpCod ()) <= 0)
-      Lay_WrongGroupExit ();
+      Err_WrongGroupExit ();
 
    /***** Get group data from database *****/
    GrpDat.GrpCod = Gbl.Crs.Grps.GrpCod;
@@ -4332,7 +4333,7 @@ void Grp_EnableFileZonesGrp (void)
 
    /***** Get group code *****/
    if ((Gbl.Crs.Grps.GrpCod = Grp_GetParamGrpCod ()) <= 0)
-      Lay_WrongGroupExit ();
+      Err_WrongGroupExit ();
 
    /***** Get group data from database *****/
    GrpDat.GrpCod = Gbl.Crs.Grps.GrpCod;
@@ -4368,7 +4369,7 @@ void Grp_DisableFileZonesGrp (void)
 
    /***** Get group code *****/
    if ((Gbl.Crs.Grps.GrpCod = Grp_GetParamGrpCod ()) <= 0)
-      Lay_WrongGroupExit ();
+      Err_WrongGroupExit ();
 
    /***** Get group data from database *****/
    GrpDat.GrpCod = Gbl.Crs.Grps.GrpCod;
@@ -4408,7 +4409,7 @@ void Grp_ChangeGroupType (void)
    /***** Get parameters from form *****/
    /* Get group code */
    if ((Gbl.Crs.Grps.GrpCod = Grp_GetParamGrpCod ()) <= 0)
-      Lay_WrongGroupExit ();
+      Err_WrongGroupExit ();
 
    /* Get the new group type */
    NewGrpTypCod = Grp_GetParamGrpTypCod ();
@@ -4462,7 +4463,7 @@ void Grp_ChangeGroupRoom (void)
    /***** Get parameters from form *****/
    /* Get group code */
    if ((Gbl.Crs.Grps.GrpCod = Grp_GetParamGrpCod ()) <= 0)
-      Lay_WrongGroupExit ();
+      Err_WrongGroupExit ();
 
    /* Get the new room */
    NewRooCod = Roo_GetParamRooCod ();
@@ -4507,7 +4508,7 @@ void Grp_ChangeMandatGrpTyp (void)
    /***** Get parameters of the form *****/
    /* Get the código of type of group */
    if ((Gbl.Crs.Grps.GrpTyp.GrpTypCod = Grp_GetParamGrpTypCod ()) <= 0)
-      Lay_WrongGrpTypExit ();
+      Err_WrongGrpTypExit ();
 
    /* Get the new type of enrolment (mandatory or voluntaria) of this type of group */
    NewMandatoryEnrolment = Par_GetParToBool ("MandatoryEnrolment");
@@ -4565,7 +4566,7 @@ void Grp_ChangeMultiGrpTyp (void)
    /***** Get parameters from the form *****/
    /* Get the code of type of group */
    if ((Gbl.Crs.Grps.GrpTyp.GrpTypCod = Grp_GetParamGrpTypCod ()) <= 0)
-      Lay_WrongGrpTypExit ();
+      Err_WrongGrpTypExit ();
 
    /* Get the new type of enrolment (single or multiple) of this type of group */
    NewMultipleEnrolment = Par_GetParToBool ("MultipleEnrolment");
@@ -4617,7 +4618,7 @@ void Grp_ChangeOpenTimeGrpTyp (void)
 
    /***** Get the code of type of group *****/
    if ((Gbl.Crs.Grps.GrpTyp.GrpTypCod = Grp_GetParamGrpTypCod ()) <= 0)
-      Lay_WrongGrpTypExit ();
+      Err_WrongGrpTypExit ();
 
    /***** Get from the database the data of this type of group *****/
    Grp_GetDataOfGroupTypeByCod (&Gbl.Crs.Grps.GrpTyp);
@@ -4663,7 +4664,7 @@ void Grp_ChangeMaxStdsGrp (void)
    /***** Get parameters of the form *****/
    /* Get group code */
    if ((Gbl.Crs.Grps.GrpCod = Grp_GetParamGrpCod ()) <= 0)
-      Lay_WrongGroupExit ();
+      Err_WrongGroupExit ();
 
    /* Get the new maximum number of students of the group */
    NewMaxStds = (unsigned)
@@ -4758,7 +4759,7 @@ void Grp_RenameGroupType (void)
    /***** Get parameters from form *****/
    /* Get the code of the group type */
    if ((Gbl.Crs.Grps.GrpTyp.GrpTypCod = Grp_GetParamGrpTypCod ()) <= 0)
-      Lay_WrongGrpTypExit ();
+      Err_WrongGrpTypExit ();
 
    /* Get the new name for the group type */
    Par_GetParToText ("GrpTypName",NewNameGrpTyp,Grp_MAX_BYTES_GROUP_TYPE_NAME);
@@ -4837,7 +4838,7 @@ void Grp_RenameGroup (void)
    /***** Get parameters from form *****/
    /* Get the code of the group */
    if ((Gbl.Crs.Grps.GrpCod = Grp_GetParamGrpCod ()) <= 0)
-      Lay_WrongGroupExit ();
+      Err_WrongGroupExit ();
 
    /* Get the new name for the group */
    Par_GetParToText ("GrpName",NewNameGrp,Grp_MAX_BYTES_GROUP_NAME);
@@ -4953,7 +4954,7 @@ void Grp_GetLstCodsGrpWanted (struct ListCodGrps *LstGrpsWanted)
    /***** Allocate memory for the strings with group codes in each type *****/
    if ((LstStrCodGrps = calloc (Gbl.Crs.Grps.GrpTypes.Num,
                                 sizeof (*LstStrCodGrps))) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Get lists with the groups that I want in each type
           in order to count the total number of groups selected *****/
@@ -4964,7 +4965,7 @@ void Grp_GetLstCodsGrpWanted (struct ListCodGrps *LstGrpsWanted)
       /***** Allocate memory for the list of group codes of this type *****/
       if ((LstStrCodGrps[NumGrpTyp] = malloc (Gbl.Crs.Grps.GrpTypes.LstGrpTypes[NumGrpTyp].NumGrps *
                                               (Cns_MAX_DECIMAL_DIGITS_LONG + 1))) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
 
       /***** Get the multiple parameter code of group of this type *****/
       snprintf (Param,sizeof (Param),"GrpCod%ld",
@@ -4990,7 +4991,7 @@ void Grp_GetLstCodsGrpWanted (struct ListCodGrps *LstGrpsWanted)
      {
       if ((LstGrpsWanted->GrpCods = calloc (LstGrpsWanted->NumGrps,
                                             sizeof (*LstGrpsWanted->GrpCods))) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
 
       /***** Get the groups *****/
       for (NumGrpTyp = 0, NumGrpWanted = 0;
diff --git a/swad_hierarchy.c b/swad_hierarchy.c
index fa10f108..c590f6f5 100644
--- a/swad_hierarchy.c
+++ b/swad_hierarchy.c
@@ -30,6 +30,7 @@
 #include <stdlib.h>		// For free
 
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_hierarchy.h"
@@ -195,7 +196,7 @@ void Hie_WriteHierarchyInBreadcrumb (void)
 
    /***** Create CSS class of links *****/
    if (asprintf (&ClassLink,"BT_LINK %s",ClassTxt) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Form to go to the system *****/
    HTM_DIV_Begin ("class=\"BC %s\"",ClassTxt);
@@ -768,7 +769,7 @@ void Hie_GetAndWriteInsCtrDegAdminBy (long UsrCod,unsigned ColSpan)
 		 }
 	       break;
 	    default:	// There are no administrators in other scopes
-	       Lay_WrongScopeExit ();
+	       Err_WrongScopeExit ();
 	       break;
            }
          HTM_TD_End ();
diff --git a/swad_holiday.c b/swad_holiday.c
index 1025752a..0176f1ad 100644
--- a/swad_holiday.c
+++ b/swad_holiday.c
@@ -32,6 +32,7 @@
 #include "swad_box.h"
 #include "swad_calendar.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_holiday.h"
@@ -370,7 +371,7 @@ void Hld_GetListHolidays (struct Hld_Holidays *Holidays)
 	 /***** Create list of holidays *****/
 	 if ((Holidays->Lst = calloc (Holidays->Num,
 	                              sizeof (*Holidays->Lst))) == NULL)
-	     Lay_NotEnoughMemoryExit ();
+	     Err_NotEnoughMemoryExit ();
 
 	 /***** Get the holidays *****/
 	 for (NumHld = 0;
@@ -384,7 +385,7 @@ void Hld_GetListHolidays (struct Hld_Holidays *Holidays)
 
 	    /* Get holiday code (row[0]) */
 	    if ((Hld->HldCod = Str_ConvertStrCodToLongCod (row[0])) <= 0)
-	       Lay_WrongHolidayExit ();
+	       Err_WrongHolidayExit ();
 
 	    /* Get place code (row[1]) */
 	    Hld->PlcCod = Str_ConvertStrCodToLongCod (row[1]);
@@ -398,7 +399,7 @@ void Hld_GetListHolidays (struct Hld_Holidays *Holidays)
 
 	    /* Get start date (row[4] holds the start date in YYYYMMDD format) */
 	    if (!(Dat_GetDateFromYYYYMMDD (&(Hld->StartDate),row[4])))
-	       Lay_WrongDateExit ();
+	       Err_WrongDateExit ();
 
 	    /* Set / get end date */
 	    switch (Hld->HldTyp)
@@ -410,7 +411,7 @@ void Hld_GetListHolidays (struct Hld_Holidays *Holidays)
 	       case Hld_NON_SCHOOL_PERIOD:	// One or more days
 	          /* Get end date (row[5] holds the end date in YYYYMMDD format) */
 		  if (!(Dat_GetDateFromYYYYMMDD (&(Hld->EndDate),row[5])))
-	             Lay_WrongDateExit ();
+	             Err_WrongDateExit ();
 		  break;
 	      }
 
@@ -445,7 +446,7 @@ static void Hld_GetDataOfHolidayByCod (struct Hld_Holiday *Hld)
 
    /***** Check if holiday code is correct *****/
    if (Hld->HldCod <= 0)
-      Lay_WrongHolidayExit ();
+      Err_WrongHolidayExit ();
 
    /***** Get data of holiday from database *****/
    if (DB_QuerySELECT (&mysql_res,"can not get data of a holiday",
@@ -496,7 +497,7 @@ static void Hld_GetDataOfHolidayByCod (struct Hld_Holiday *Hld)
 
       /* Get start date (row[3] holds the start date in YYYYMMDD format) */
       if (!(Dat_GetDateFromYYYYMMDD (&(Hld->StartDate),row[3])))
-	 Lay_WrongDateExit ();
+	 Err_WrongDateExit ();
 
       /* Set / get end date */
       switch (Hld->HldTyp)
@@ -508,7 +509,7 @@ static void Hld_GetDataOfHolidayByCod (struct Hld_Holiday *Hld)
 	 case Hld_NON_SCHOOL_PERIOD:	// One or more days
 	    /* Get end date (row[4] holds the end date in YYYYMMDD format) */
 	    if (!(Dat_GetDateFromYYYYMMDD (&(Hld->EndDate),row[4])))
-	       Lay_WrongDateExit ();
+	       Err_WrongDateExit ();
 	    break;
 	}
 
@@ -542,10 +543,10 @@ static Hld_HolidayType_t Hld_GetTypeOfHoliday (const char *UnsignedStr)
    unsigned UnsignedNum;
 
    if (sscanf (UnsignedStr,"%u",&UnsignedNum) != 1)
-      Lay_WrongHolidayExit ();
+      Err_WrongHolidayExit ();
 
    if (UnsignedNum >= Hld_NUM_TYPES_HOLIDAY)
-      Lay_WrongHolidayExit ();
+      Err_WrongHolidayExit ();
 
    return (Hld_HolidayType_t) UnsignedNum;
   }
@@ -721,7 +722,7 @@ void Hld_RemoveHoliday (void)
 
    /***** Get holiday code *****/
    if ((Hld_EditingHld->HldCod = Hld_GetParamHldCod ()) <= 0)
-      Lay_WrongHolidayExit ();
+      Err_WrongHolidayExit ();
 
    /***** Get data of the holiday from database *****/
    Hld_GetDataOfHolidayByCod (Hld_EditingHld);
@@ -753,7 +754,7 @@ void Hld_ChangeHolidayPlace (void)
    /***** Get parameters from form *****/
    /* Get the code of the holiday */
    if ((Hld_EditingHld->HldCod = Hld_GetParamHldCod ()) <= 0)
-      Lay_WrongHolidayExit ();
+      Err_WrongHolidayExit ();
 
    /* Get the new place for the holiday */
    NewPlace.PlcCod = Plc_GetParamPlcCod ();
@@ -794,7 +795,7 @@ void Hld_ChangeHolidayType (void)
 
    /***** Get the code of the holiday *****/
    if ((Hld_EditingHld->HldCod = Hld_GetParamHldCod ()) <= 0)
-      Lay_WrongHolidayExit ();
+      Err_WrongHolidayExit ();
 
    /***** Get from the database the data of the holiday *****/
    Hld_GetDataOfHolidayByCod (Hld_EditingHld);
@@ -853,7 +854,7 @@ static void Hld_ChangeDate (Hld_StartOrEndDate_t StartOrEndDate)
 
    /***** Get the code of the holiday *****/
    if ((Hld_EditingHld->HldCod = Hld_GetParamHldCod ()) <= 0)
-      Lay_WrongHolidayExit ();
+      Err_WrongHolidayExit ();
 
    /***** Get from the database the data of the holiday *****/
    Hld_GetDataOfHolidayByCod (Hld_EditingHld);
@@ -926,7 +927,7 @@ void Hld_RenameHoliday (void)
    /***** Get parameters from form *****/
    /* Get the code of the holiday */
    if ((Hld_EditingHld->HldCod = Hld_GetParamHldCod ()) <= 0)
-      Lay_WrongHolidayExit ();
+      Err_WrongHolidayExit ();
 
    /* Get the new name for the holiday */
    Par_GetParToText ("Name",NewHldName,Hld_MAX_BYTES_HOLIDAY_NAME);
@@ -1214,11 +1215,11 @@ static void Hld_EditingHolidayConstructor (void)
   {
    /***** Pointer must be NULL *****/
    if (Hld_EditingHld != NULL)
-      Lay_WrongHolidayExit ();
+      Err_WrongHolidayExit ();
 
    /***** Allocate memory for holiday *****/
    if ((Hld_EditingHld = malloc (sizeof (*Hld_EditingHld))) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Reset place *****/
    Hld_EditingHld->HldCod = -1L;
diff --git a/swad_indicator.c b/swad_indicator.c
index a2d3c2e1..cc97640c 100644
--- a/swad_indicator.c
+++ b/swad_indicator.c
@@ -32,6 +32,7 @@
 #include "swad_box.h"
 #include "swad_database.h"
 #include "swad_department.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_forum.h"
 #include "swad_global.h"
@@ -636,7 +637,7 @@ static unsigned Ind_GetTableOfCourses (const struct Ind_Indicators *Indicators,
 			    Gbl.Hierarchy.Crs.CrsCod);
          break;
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 break;
      }
 
@@ -723,7 +724,7 @@ static void Ind_GetNumCoursesWithIndicators (unsigned NumCrssWithIndicatorYes[1
 
       /* Get course code (row[2]) */
       if ((CrsCod = Str_ConvertStrCodToLongCod (row[2])) < 0)
-         Lay_WrongCourseExit ();
+         Err_WrongCourseExit ();
 
       /* Get stored number of indicators of this course */
       NumIndicators = Ind_GetAndUpdateNumIndicatorsCrs (CrsCod);
@@ -991,7 +992,7 @@ static void Ind_ShowTableOfCoursesWithIndicators (const struct Ind_Indicators *I
 
       /* Get course code (row[2]) */
       if ((CrsCod = Str_ConvertStrCodToLongCod (row[2])) < 0)
-         Lay_WrongCourseExit ();
+         Err_WrongCourseExit ();
 
       /* Get stored number of indicators of this course */
       NumIndicators = Ind_GetAndUpdateNumIndicatorsCrs (CrsCod);
@@ -1385,7 +1386,7 @@ int Ind_GetNumIndicatorsCrsFromDB (long CrsCod)
 
       /***** Get number of indicators (row[0]) *****/
       if (sscanf (row[0],"%d",&NumIndicatorsFromDB) != 1)
-	 Lay_ShowErrorAndExit ("Error when getting number of indicators.");
+	 Err_ShowErrorAndExit ("Error when getting number of indicators.");
      }
 
    /***** Free structure that stores the query result *****/
diff --git a/swad_info.c b/swad_info.c
index 08ea7369..0565f5ee 100644
--- a/swad_info.c
+++ b/swad_info.c
@@ -36,6 +36,7 @@
 #include "swad_action.h"
 #include "swad_box.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_HTML.h"
@@ -1834,7 +1835,7 @@ static bool Inf_CheckAndShowRichTxt (void)
 
       /* Open Markdown file for writing */
       if ((FileMD = fopen (PathFileMD,"wb")) == NULL)
-	 Lay_ShowErrorAndExit ("Can not create temporary Markdown file.");
+	 Err_ShowErrorAndExit ("Can not create temporary Markdown file.");
 
       /* Write text into Markdown file */
       fprintf (FileMD,"%s",TxtMD);
@@ -1877,7 +1878,7 @@ static bool Inf_CheckAndShowRichTxt (void)
 	        PathFileHTML);
       ReturnCode = system (Command);
       if (ReturnCode == -1)
-	 Lay_ShowErrorAndExit ("Error when running command to convert from Markdown to HTML.");
+	 Err_ShowErrorAndExit ("Error when running command to convert from Markdown to HTML.");
 
       /***** Remove Markdown file *****/
       unlink (PathFileMD);
@@ -1885,7 +1886,7 @@ static bool Inf_CheckAndShowRichTxt (void)
       /***** Copy HTML file just created to HTML output *****/
       /* Open temporary HTML file for reading */
       if ((FileHTML = fopen (PathFileHTML,"rb")) == NULL)
-	 Lay_ShowErrorAndExit ("Can not open temporary HTML file.");
+	 Err_ShowErrorAndExit ("Can not open temporary HTML file.");
 
       /* Copy from temporary HTML file to output file */
       Fil_FastCopyOfOpenFiles (FileHTML,Gbl.F.Out);
@@ -2261,7 +2262,7 @@ void Inf_ReceivePagInfo (void)
 	         }
 	      }
             else
-               Lay_ShowErrorAndExit ("Can not unzip file.");
+               Err_ShowErrorAndExit ("Can not unzip file.");
            }
          else
             Ale_ShowAlert (Ale_ERROR,"Error uploading file.");
diff --git a/swad_institution.c b/swad_institution.c
index 6e53b255..2644c332 100644
--- a/swad_institution.c
+++ b/swad_institution.c
@@ -32,6 +32,7 @@
 
 #include "swad_database.h"
 #include "swad_department.h"
+#include "swad_error.h"
 #include "swad_figure.h"
 #include "swad_figure_cache.h"
 #include "swad_form.h"
@@ -651,7 +652,7 @@ void Ins_GetBasicListOfInstitutions (long CtyCod)
       /***** Create list with institutions *****/
       if ((Gbl.Hierarchy.Inss.Lst = calloc ((size_t) Gbl.Hierarchy.Inss.Num,
                                             sizeof (*Gbl.Hierarchy.Inss.Lst))) == NULL)
-          Lay_NotEnoughMemoryExit ();
+          Err_NotEnoughMemoryExit ();
 
       /***** Get the institutions *****/
       for (NumIns = 0;
@@ -733,7 +734,7 @@ void Ins_GetFullListOfInstitutions (long CtyCod)
       /***** Create list with institutions *****/
       if ((Gbl.Hierarchy.Inss.Lst = calloc ((size_t) Gbl.Hierarchy.Inss.Num,
                                             sizeof (*Gbl.Hierarchy.Inss.Lst))) == NULL)
-          Lay_NotEnoughMemoryExit ();
+          Err_NotEnoughMemoryExit ();
 
       /***** Get the institutions *****/
       for (NumIns = 0;
@@ -835,14 +836,14 @@ static void Ins_GetDataOfInstitFromRow (struct Ins_Instit *Ins,MYSQL_ROW row)
   {
    /***** Get institution code (row[0]) *****/
    if ((Ins->InsCod = Str_ConvertStrCodToLongCod (row[0])) < 0)
-      Lay_WrongInstitExit ();
+      Err_WrongInstitExit ();
 
    /***** Get country code (row[1]) *****/
    Ins->CtyCod = Str_ConvertStrCodToLongCod (row[1]);
 
    /***** Get institution status (row[2]) *****/
    if (sscanf (row[2],"%u",&(Ins->Status)) != 1)
-      Lay_WrongStatusExit ();
+      Err_WrongStatusExit ();
 
    /***** Get requester user's code (row[3]) *****/
    Ins->RequesterUsrCod = Str_ConvertStrCodToLongCod (row[3]);
@@ -1030,7 +1031,7 @@ void Ins_WriteSelectorOfInstitution (void)
 
          /* Get institution code (row[0]) */
          if ((InsCod = Str_ConvertStrCodToLongCod (row[0])) < 0)
-            Lay_WrongInstitExit ();
+            Err_WrongInstitExit ();
 
          /* Write option */
 	 HTM_OPTION (HTM_Type_LONG,&InsCod,
@@ -1314,7 +1315,7 @@ long Ins_GetAndCheckParamOtherInsCod (long MinCodAllowed)
 
    /***** Get and check parameter with code of institution *****/
    if ((InsCod = Ins_GetParamOtherInsCod ()) < MinCodAllowed)
-      Lay_WrongInstitExit ();
+      Err_WrongInstitExit ();
 
    return InsCod;
   }
@@ -1346,7 +1347,7 @@ void Ins_RemoveInstitution (void)
 
    /***** Check if this institution has users *****/
    if (!Ins_CheckIfICanEdit (Ins_EditingIns))
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
    else if (Ctr_GetNumCtrsInIns (Ins_EditingIns->InsCod))
       // Institution has centers ==> don't remove
       Ale_CreateAlert (Ale_WARNING,NULL,
@@ -1618,7 +1619,7 @@ void Ins_ChangeInsStatus (void)
 	                              (unsigned long) Ins_MAX_STATUS,
                                       (unsigned long) Ins_WRONG_STATUS);
    if (Status == Ins_WRONG_STATUS)
-      Lay_WrongStatusExit ();
+      Err_WrongStatusExit ();
    StatusTxt = Ins_GetStatusTxtFromStatusBits (Status);
    Status = Ins_GetStatusBitsFromStatusTxt (StatusTxt);	// New status
 
@@ -1702,7 +1703,7 @@ static void Ins_PutFormToCreateInstitution (void)
    else if (Gbl.Usrs.Me.Role.Max >= Rol_GST)
       Frm_BeginForm (ActReqIns);
    else
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Begin box and table *****/
    Box_BoxTableBegin (NULL,Txt_New_institution,
@@ -2174,11 +2175,11 @@ static void Ins_EditingInstitutionConstructor (void)
   {
    /***** Pointer must be NULL *****/
    if (Ins_EditingIns != NULL)
-      Lay_WrongInstitExit ();
+      Err_WrongInstitExit ();
 
    /***** Allocate memory for institution *****/
    if ((Ins_EditingIns = malloc (sizeof (*Ins_EditingIns))) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Reset institution *****/
    Ins_EditingIns->InsCod             = -1L;
diff --git a/swad_institution_config.c b/swad_institution_config.c
index 12fda97c..455df6d8 100644
--- a/swad_institution_config.c
+++ b/swad_institution_config.c
@@ -33,6 +33,7 @@
 
 #include "swad_database.h"
 #include "swad_department.h"
+#include "swad_error.h"
 #include "swad_figure_cache.h"
 #include "swad_form.h"
 #include "swad_global.h"
@@ -264,7 +265,7 @@ static void InsCfg_GetCoordAndZoom (struct Coordinates *Coord,unsigned *Zoom)
 		   " AND Latitude<>0"
 		   " AND Longitude<>0",
 		 Gbl.Hierarchy.Ins.InsCod) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    Map_GetCoordAndZoom (Coord,Zoom,Query);
    free (Query);
   }
diff --git a/swad_layout.c b/swad_layout.c
index 5b7bd5cc..d1e6d60e 100644
--- a/swad_layout.c
+++ b/swad_layout.c
@@ -39,6 +39,7 @@
 #include "swad_config.h"
 #include "swad_connected.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_exam_session.h"
 #include "swad_firewall.h"
 #include "swad_follow.h"
@@ -86,8 +87,6 @@ extern struct Globals Gbl;
 /***************************** Private prototypes ****************************/
 /*****************************************************************************/
 
-static void Lay_WriteEndOfPage (void);
-
 static void Lay_WritePageTitle (void);
 
 static void Lay_WriteRedirToMyLangOnLogIn (void);
@@ -107,7 +106,6 @@ static void Lay_WriteTitleAction (void);
 static void Lay_ShowLeftColumn (void);
 static void Lay_ShowRightColumn (void);
 
-static void Lay_WriteAboutZone (void);
 static void Lay_WriteFootFromHTMLFile (void);
 
 static void Lay_HelpTextEditor (const char *Text,const char *InlineMath,const char *Equation);
@@ -412,7 +410,7 @@ void Lay_WriteHTTPStatus204NoContent (void)
 /************************ Write the end of the page **************************/
 /*****************************************************************************/
 
-static void Lay_WriteEndOfPage (void)
+void Lay_WriteEndOfPage (void)
   {
    if (!Gbl.Layout.DivsEndWritten)
      {
@@ -1369,556 +1367,11 @@ void Lay_PutContextualCheckbox (Act_Action_t NextAction,
 			// jumping to the next line on narrow screens
   }
 
-/*****************************************************************************/
-/********** Write error message and exit when not enough memory **************/
-/*****************************************************************************/
-
-void Lay_NotEnoughMemoryExit (void)
-  {
-   Lay_ShowErrorAndExit ("Not enough memory.");
-  }
-
-/*****************************************************************************/
-/************* Write error message and exit when wrong action ****************/
-/*****************************************************************************/
-
-void Lay_WrongActionExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong action.");
-  }
-
-/*****************************************************************************/
-/************* Write error message and exit when wrong scope *****************/
-/*****************************************************************************/
-
-void Lay_WrongScopeExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong scope.");
-  }
-
-/*****************************************************************************/
-/********* Write error message and exit                              *********/
-/********* when wrong country, institution, center, degree or course *********/
-/*****************************************************************************/
-
-void Lay_WrongCountrExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong country.");
-  }
-
-void Lay_WrongInstitExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong institution.");
-  }
-
-void Lay_WrongCenterExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong center.");
-  }
-
-void Lay_WrongDegTypExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong degree type.");
-  }
-
-void Lay_WrongDegreeExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong degree.");
-  }
-
-void Lay_WrongCourseExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong course.");
-  }
-
-/*****************************************************************************/
-/*********** Write error message and exit when wrong department **************/
-/*****************************************************************************/
-
-void Lay_WrongDepartmentExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong department.");
-  }
-
-/*****************************************************************************/
-/************** Write error message and exit when wrong place ****************/
-/*****************************************************************************/
-
-void Lay_WrongPlaceExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong department.");
-  }
-
-/*****************************************************************************/
-/************* Write error message and exit when wrong order *****************/
-/*****************************************************************************/
-
-void Lay_WrongOrderExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong order.");
-  }
-
-/*****************************************************************************/
-/************* Write error message and exit when wrong status ****************/
-/*****************************************************************************/
-
-void Lay_WrongStatusExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong status.");
-  }
-
-/*****************************************************************************/
-/************* Write error message and exit when wrong date ****************/
-/*****************************************************************************/
-
-void Lay_WrongDateExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong date.");
-  }
-
-/*****************************************************************************/
-/************** Write error message and exit when wrong plugin ***************/
-/*****************************************************************************/
-
-void Lay_WrongPluginExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong plugin.");
-  }
-
-/*****************************************************************************/
-/********** Write error message and exit when wrong items list/item **********/
-/*****************************************************************************/
-
-void Lay_WrongItemsListExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong items list.");
-  }
-
-void Lay_WrongItemExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong item.");
-  }
-
-/*****************************************************************************/
-/********** Write error message and exit when wrong syllabus format **********/
-/*****************************************************************************/
-
-void Lay_WrongSyllabusFormatExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong syllabus format.");
-  }
-
-/*****************************************************************************/
-/*********** Write error message and exit when wrong file browser ************/
-/*****************************************************************************/
-
-void Lay_WrongFileBrowserExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong file browser.");
-  }
-
-/*****************************************************************************/
-/*********** Write error message and exit when wrong copy source *************/
-/*****************************************************************************/
-
-void Lay_WrongCopySrcExit (void)
-  {
-   Lay_ShowErrorAndExit ("The copy source does not exist.");
-  }
-
-/*****************************************************************************/
-/********** Write error message and exit when wrong number of rows ***********/
-/*****************************************************************************/
-
-void Lay_WrongNumberOfRowsExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong number of rows.");
-  }
-
-/*****************************************************************************/
-/********* Write error message and exit when wrong group type/group **********/
-/*****************************************************************************/
-
-void Lay_WrongGrpTypExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong group type.");
-  }
-
-void Lay_WrongGroupExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong group.");
-  }
-
-/*****************************************************************************/
-/************* Write error message and exit when wrong order *****************/
-/*****************************************************************************/
-
-void Lay_WrongTypeOfViewExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong type of view.");
-  }
-
-/*****************************************************************************/
-/*********** Write error message and exit when wrong banner/link *************/
-/*****************************************************************************/
-
-void Lay_WrongBannerExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong banner.");
-  }
-
-void Lay_WrongLinkExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong link.");
-  }
-
-/*****************************************************************************/
-/************* Write error message and exit when wrong holiday ***************/
-/*****************************************************************************/
-
-void Lay_WrongHolidayExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong holiday.");
-  }
-
-/*****************************************************************************/
-/********** Write error message and exit when wrong building/room ************/
-/*****************************************************************************/
-
-void Lay_WrongBuildingExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong building.");
-  }
-
-void Lay_WrongRoomExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong room.");
-  }
-
-/*****************************************************************************/
-/*********** Write error message and exit when wrong record field ************/
-/*****************************************************************************/
-
-void Lay_WrongRecordFieldExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong record field.");
-  }
-
-/*****************************************************************************/
-/*********** Write error message and exit when wrong assignment **************/
-/*****************************************************************************/
-
-void Lay_WrongAssignmentExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong assignment.");
-  }
-
-/*****************************************************************************/
-/************* Write error message and exit when wrong project ***************/
-/*****************************************************************************/
-
-void Lay_WrongProjectExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong project.");
-  }
-
-/*****************************************************************************/
-/********** Write error message and exit when wrong call for exam ************/
-/*****************************************************************************/
-
-void Lay_WrongCallForExamExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong call for exam.");
-  }
-
-/*****************************************************************************/
-/************** Write error message and exit when wrong tag *****************/
-/*****************************************************************************/
-
-void Lay_WrongTagExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong tag.");
-  }
-
-/*****************************************************************************/
-/************** Write error message and exit when wrong test *****************/
-/*****************************************************************************/
-
-void Lay_WrongTestExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong test.");
-  }
-
-/*****************************************************************************/
-/************** Write error message and exit when wrong exam *****************/
-/*****************************************************************************/
-
-void Lay_WrongExamExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong exam.");
-  }
-
-/*****************************************************************************/
-/********* Write error message and exit when wrong set of questions **********/
-/*****************************************************************************/
-
-void Lay_WrongSetExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong set of questions.");
-  }
-
-/*****************************************************************************/
-/************* Write error message and exit when wrong question **************/
-/*****************************************************************************/
-
-void Lay_WrongQuestionExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong question.");
-  }
-
-void Lay_WrongQuestionIndexExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong question index.");
-  }
-
-/*****************************************************************************/
-/************** Write error message and exit when wrong answer ***************/
-/*****************************************************************************/
-
-void Lay_WrongAnswerExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong answer.");
-  }
-
-void Lay_WrongAnswerIndexExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong answer index.");
-  }
-
-/*****************************************************************************/
-/*********** Write error message and exit when wrong exam session ************/
-/*****************************************************************************/
-
-void Lay_WrongExamSessionExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong exam session.");
-  }
-
-/*****************************************************************************/
-/************ Write error message and exit when wrong game/match *************/
-/*****************************************************************************/
-
-void Lay_WrongGameExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong game.");
-  }
-
-void Lay_WrongMatchExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong match.");
-  }
-
-/*****************************************************************************/
-/************** Write error message and exit when wrong survey ***************/
-/*****************************************************************************/
-
-void Lay_WrongSurveyExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong survey.");
-  }
-
-/*****************************************************************************/
-/*** Write error message and exit when wrong parameter "who" (which users) ***/
-/*****************************************************************************/
-
-void Lay_WrongWhoExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong parameter who.");
-  }
-
-/*****************************************************************************/
-/**************** Write error message and exit when wrong event **************/
-/*****************************************************************************/
-
-void Lay_WrongEventExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong event.");
-  }
-
-/*****************************************************************************/
-/*********** Write error message and exit when wrong announcement ************/
-/*****************************************************************************/
-
-void Lay_WrongAnnouncementExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong announcement.");
-  }
-
-/*****************************************************************************/
-/************** Write error message and exit when wrong notice ***************/
-/*****************************************************************************/
-
-void Lay_WrongNoticeExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong notice.");
-  }
-
-/*****************************************************************************/
-/************ Write error message and exit when wrong forum/post *************/
-/*****************************************************************************/
-
-void Lay_WrongForumExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong forum.");
-  }
-
-void Lay_WrongPostExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong post.");
-  }
-
-/*****************************************************************************/
-/************** Write error message and exit when wrong message **************/
-/*****************************************************************************/
-
-void Lay_WrongMessageExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong message.");
-  }
-
-/*****************************************************************************/
-/************ Write error message and exit when wrong mail domain ************/
-/*****************************************************************************/
-
-void Lay_WrongMailDomainExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong mail domain.");
-  }
-
-/*****************************************************************************/
-/************* Show error message about wrong role and exit ******************/
-/*****************************************************************************/
-
-void Lay_WrongRoleExit (void)
-  {
-   Lay_ShowErrorAndExit ("Wrong role.");
-  }
-
-/*****************************************************************************/
-/************ Write error message and exit when user does not exists *********/
-/*****************************************************************************/
-
-void Lay_WrongUserExit (void)
-  {
-   extern const char *Txt_The_user_does_not_exist;
-
-   Lay_ShowErrorAndExit (Txt_The_user_does_not_exist);
-  }
-
-/*****************************************************************************/
-/*** Write error message and exit when no permission to perform an action ****/
-/*****************************************************************************/
-
-void Lay_NoPermissionExit (void)
-  {
-   extern const char *Txt_You_dont_have_permission_to_perform_this_action;
-
-   Lay_ShowErrorAndExit (Txt_You_dont_have_permission_to_perform_this_action);
-  }
-
-/*****************************************************************************/
-/******* Write error message, close files, remove lock file, and exit ********/
-/*****************************************************************************/
-
-void Lay_ShowErrorAndExit (const char *Txt)
-  {
-   /***** Unlock tables if locked *****/
-   if (Gbl.DB.LockedTables)
-     {
-      Gbl.DB.LockedTables = false;
-      mysql_query (&Gbl.mysql,"UNLOCK TABLES");
-     }
-
-   if (!Gbl.WebService.IsWebService)
-     {
-      /****** If start of page is not written yet, do it now ******/
-      if (!Gbl.Layout.HTMLStartWritten)
-	 Lay_WriteStartOfPage ();
-
-      /***** Write possible error message *****/
-      if (Txt)
-         Ale_ShowAlert (Ale_ERROR,Txt);
-
-      /***** Finish the page, except </body> and </html> *****/
-      Lay_WriteEndOfPage ();
-     }
-
-   /***** Free memory and close all the open files *****/
-   Gbl_Cleanup ();
-
-   /***** Page is generated (except </body> and </html>).
-          Compute time to generate page *****/
-   if (!Gbl.Action.IsAJAXAutoRefresh)
-      Gbl.TimeGenerationInMicroseconds = (long) Sta_ComputeTimeToGeneratePage ();
-
-   if (Gbl.WebService.IsWebService)		// Serving a plugin request
-     {
-      /***** Log access *****/
-      Gbl.TimeSendInMicroseconds = 0L;
-      Log_LogAccess (Txt);
-     }
-   else
-     {
-      /***** Send page.
-             The HTML output is now in Gbl.F.Out file ==>
-             ==> copy it to standard output *****/
-      rewind (Gbl.F.Out);
-      Fil_FastCopyOfOpenFiles (Gbl.F.Out,stdout);
-      Fil_CloseAndRemoveFileForHTMLOutput ();
-
-      if (!Gbl.Action.IsAJAXAutoRefresh)
-	{
-	 /***** Compute time to send page *****/
-	 Sta_ComputeTimeToSendPage ();
-
-	 /***** Log access *****/
-	 Log_LogAccess (Txt);
-
-	 /***** Update last data for next time *****/
-	 if (Gbl.Usrs.Me.Logged)
-	   {
-	    Usr_UpdateMyLastData ();
-	    Crs_UpdateCrsLast ();
-	   }
-
-	 /***** End the output *****/
-	 if (!Gbl.Layout.HTMLEndWritten)
-	   {
-	    // Here Gbl.F.Out is stdout
-	    if (Act_GetBrowserTab (Gbl.Action.Act) == Act_BRW_1ST_TAB)
-	       Lay_WriteAboutZone ();
-
-	    HTM_Txt ("</body>\n"
-		     "</html>\n");
-	    Gbl.Layout.HTMLEndWritten = true;
-	   }
-	}
-     }
-
-   /***** Close database connection *****/
-   DB_CloseDBConnection ();
-
-   /***** Exit *****/
-   if (Gbl.WebService.IsWebService)
-      API_Exit (Txt);
-   exit (0);
-  }
-
 /*****************************************************************************/
 /***************** Write about zone at the end of the page *******************/
 /*****************************************************************************/
 
-static void Lay_WriteAboutZone (void)
+void Lay_WriteAboutZone (void)
   {
    extern const char *Txt_About_X;
    extern const char *Txt_Questions_and_problems;
diff --git a/swad_layout.h b/swad_layout.h
index 2435d322..18645a4c 100644
--- a/swad_layout.h
+++ b/swad_layout.h
@@ -50,6 +50,8 @@ void Lay_WriteStartOfPage (void);
 
 void Lay_WriteHTTPStatus204NoContent (void);
 
+void Lay_WriteEndOfPage (void);
+
 void Lay_PutContextualLinkOnlyIcon (Act_Action_t NextAction,const char *Anchor,
 				    void (*FuncParams) (void *Args),void *Args,
 				    const char *Icon,
@@ -69,63 +71,7 @@ void Lay_PutContextualCheckbox (Act_Action_t NextAction,
                                 bool Checked,bool Disabled,
                                 const char *Title,const char *Text);
 
-void Lay_NotEnoughMemoryExit (void);
-void Lay_WrongActionExit (void);
-void Lay_WrongScopeExit (void);
-void Lay_WrongCountrExit (void);
-void Lay_WrongInstitExit (void);
-void Lay_WrongCenterExit (void);
-void Lay_WrongDegTypExit (void);
-void Lay_WrongDegreeExit (void);
-void Lay_WrongCourseExit (void);
-void Lay_WrongDepartmentExit (void);
-void Lay_WrongPlaceExit (void);
-void Lay_WrongOrderExit (void);
-void Lay_WrongStatusExit (void);
-void Lay_WrongDateExit (void);
-void Lay_WrongPluginExit (void);
-void Lay_WrongItemsListExit (void);
-void Lay_WrongItemExit (void);
-void Lay_WrongSyllabusFormatExit (void);
-void Lay_WrongFileBrowserExit (void);
-void Lay_WrongCopySrcExit (void);
-void Lay_WrongNumberOfRowsExit (void);
-void Lay_WrongGrpTypExit (void);
-void Lay_WrongGroupExit (void);
-void Lay_WrongTypeOfViewExit (void);
-void Lay_WrongBannerExit (void);
-void Lay_WrongLinkExit (void);
-void Lay_WrongHolidayExit (void);
-void Lay_WrongBuildingExit (void);
-void Lay_WrongRoomExit (void);
-void Lay_WrongRecordFieldExit (void);
-void Lay_WrongAssignmentExit (void);
-void Lay_WrongProjectExit (void);
-void Lay_WrongCallForExamExit (void);
-void Lay_WrongTagExit (void);
-void Lay_WrongTestExit (void);
-void Lay_WrongExamExit (void);
-void Lay_WrongSetExit (void);
-void Lay_WrongQuestionExit (void);
-void Lay_WrongQuestionIndexExit (void);
-void Lay_WrongAnswerExit (void);
-void Lay_WrongAnswerIndexExit (void);
-void Lay_WrongExamSessionExit (void);
-void Lay_WrongGameExit (void);
-void Lay_WrongMatchExit (void);
-void Lay_WrongSurveyExit (void);
-void Lay_WrongWhoExit (void);
-void Lay_WrongEventExit (void);
-void Lay_WrongAnnouncementExit (void);
-void Lay_WrongNoticeExit (void);
-void Lay_WrongForumExit (void);
-void Lay_WrongPostExit (void);
-void Lay_WrongMessageExit (void);
-void Lay_WrongMailDomainExit (void);
-void Lay_WrongRoleExit (void);
-void Lay_WrongUserExit (void);
-void Lay_NoPermissionExit (void);
-void Lay_ShowErrorAndExit (const char *Txt);
+void Lay_WriteAboutZone (void);
 
 void Lay_RefreshNotifsAndConnected (void);
 void Lay_RefreshLastClicks (void);
diff --git a/swad_link.c b/swad_link.c
index 463411cf..fe5e6f53 100644
--- a/swad_link.c
+++ b/swad_link.c
@@ -33,6 +33,7 @@
 #include "swad_box.h"
 #include "swad_constant.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_HTML.h"
@@ -307,7 +308,7 @@ void Lnk_GetListLinks (void)
 	 /***** Create list with places *****/
 	 if ((Gbl.Links.Lst = calloc ((size_t) Gbl.Links.Num,
 	                              sizeof (*Gbl.Links.Lst))) == NULL)
-	     Lay_NotEnoughMemoryExit ();
+	     Err_NotEnoughMemoryExit ();
 
 	 /***** Get the links *****/
 	 for (NumLnk = 0;
@@ -321,7 +322,7 @@ void Lnk_GetListLinks (void)
 
 	    /* Get link code (row[0]) */
 	    if ((Lnk->LnkCod = Str_ConvertStrCodToLongCod (row[0])) <= 0)
-	       Lay_WrongLinkExit ();
+	       Err_WrongLinkExit ();
 
             /* Get the short name (row[0]), the full name (row[1])
                and de URL (row[2]) of the link */
@@ -494,7 +495,7 @@ void Lnk_RemoveLink (void)
 
    /***** Get link code *****/
    if ((Lnk_EditingLnk->LnkCod = Lnk_GetParamLnkCod ()) <= 0)
-      Lay_WrongLinkExit ();
+      Err_WrongLinkExit ();
 
    /***** Get data of the link from database *****/
    Lnk_GetDataOfLinkByCod (Lnk_EditingLnk);
@@ -571,7 +572,7 @@ static void Lnk_RenameLink (Cns_ShrtOrFullName_t ShrtOrFullName)
    /***** Get parameters from form *****/
    /* Get the code of the link */
    if ((Lnk_EditingLnk->LnkCod = Lnk_GetParamLnkCod ()) <= 0)
-      Lay_WrongLinkExit ();
+      Err_WrongLinkExit ();
 
    /* Get the new name for the link */
    Par_GetParToText (ParamName,NewLnkName,MaxBytes);
@@ -660,7 +661,7 @@ void Lnk_ChangeLinkWWW (void)
    /***** Get parameters from form *****/
    /* Get the code of the link */
    if ((Lnk_EditingLnk->LnkCod = Lnk_GetParamLnkCod ()) <= 0)
-      Lay_WrongLinkExit ();
+      Err_WrongLinkExit ();
 
    /* Get the new WWW for the link */
    Par_GetParToText ("WWW",NewWWW,Cns_MAX_BYTES_WWW);
@@ -864,11 +865,11 @@ static void Lnk_EditingLinkConstructor (void)
   {
    /***** Pointer must be NULL *****/
    if (Lnk_EditingLnk != NULL)
-      Lay_WrongLinkExit ();
+      Err_WrongLinkExit ();
 
    /***** Allocate memory for link *****/
    if ((Lnk_EditingLnk = malloc (sizeof (*Lnk_EditingLnk))) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Reset link *****/
    Lnk_EditingLnk->LnkCod      = -1L;
diff --git a/swad_logo.c b/swad_logo.c
index 4b3dede9..67ce0111 100644
--- a/swad_logo.c
+++ b/swad_logo.c
@@ -32,6 +32,7 @@
 
 #include "swad_action.h"
 #include "swad_box.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_HTML.h"
@@ -163,16 +164,16 @@ void Lgo_DrawLogo (Hie_Lvl_Level_t Scope,long Cod,const char *AltText,
 			     Cfg_URL_SWAD_PUBLIC,Folder,
 			     (unsigned) (Cod % 100),
 			     (unsigned) Cod) < 0)
-		  Lay_NotEnoughMemoryExit ();
+		  Err_NotEnoughMemoryExit ();
 	       if (asprintf (&Icon,"%u.png",(unsigned) Cod) < 0)
-		  Lay_NotEnoughMemoryExit ();
+		  Err_NotEnoughMemoryExit ();
 	      }
 	    else
 	      {
 	       if (asprintf (&URL,"%s",Cfg_URL_ICON_PUBLIC) < 0)
-		  Lay_NotEnoughMemoryExit ();
+		  Err_NotEnoughMemoryExit ();
 	       if (asprintf (&Icon,"%s",HieIcon[Scope]) < 0)
-		  Lay_NotEnoughMemoryExit ();
+		  Err_NotEnoughMemoryExit ();
 	      }
 	    ClassNotEmpty = false;
 	    if (Class)
diff --git a/swad_mail.c b/swad_mail.c
index b109d884..9b117fbf 100644
--- a/swad_mail.c
+++ b/swad_mail.c
@@ -34,6 +34,7 @@
 #include "swad_account.h"
 #include "swad_box.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_HTML.h"
@@ -312,7 +313,7 @@ static void Mai_GetListMailDomainsAllowedForNotif (void)
       /***** Create list with places *****/
       if ((Gbl.Mails.Lst = calloc ((size_t) Gbl.Mails.Num,
                                    sizeof (*Gbl.Mails.Lst))) == NULL)
-          Lay_NotEnoughMemoryExit ();
+          Err_NotEnoughMemoryExit ();
 
       /***** Get the mail domains *****/
       for (NumMai = 0;
@@ -326,7 +327,7 @@ static void Mai_GetListMailDomainsAllowedForNotif (void)
 
          /* Get mail code (row[0]) */
          if ((Mai->MaiCod = Str_ConvertStrCodToLongCod (row[0])) <= 0)
-            Lay_WrongMailDomainExit ();
+            Err_WrongMailDomainExit ();
 
          /* Get the mail domain (row[1]) and the mail domain info (row[2]) */
          Str_Copy (Mai->Domain,row[1],sizeof (Mai->Domain) - 1);
@@ -575,7 +576,7 @@ void Mai_RemoveMailDomain (void)
 
    /***** Get mail code *****/
    if ((Mai_EditingMai->MaiCod = Mai_GetParamMaiCod ()) <= 0)
-      Lay_WrongMailDomainExit ();
+      Err_WrongMailDomainExit ();
 
    /***** Get data of the mail from database *****/
    Mai_GetDataOfMailDomainByCod (Mai_EditingMai);
@@ -652,7 +653,7 @@ static void Mai_RenameMailDomain (Cns_ShrtOrFullName_t ShrtOrFullName)
    /***** Get parameters from form *****/
    /* Get the code of the mail */
    if ((Mai_EditingMai->MaiCod = Mai_GetParamMaiCod ()) <= 0)
-      Lay_WrongMailDomainExit ();
+      Err_WrongMailDomainExit ();
 
    /* Get the new name for the mail */
    Par_GetParToText (ParamName,NewMaiName,MaxBytes);
@@ -971,12 +972,12 @@ static void Mai_ListEmails (__attribute__((unused)) void *Args)
 	       HTM_Txt (", ");
 	       LengthStrAddr ++;
 	       if (LengthStrAddr > Mai_MAX_BYTES_STR_ADDR)
-		  Lay_ShowErrorAndExit ("The space allocated to store email addresses is full.");
+		  Err_ShowErrorAndExit ("The space allocated to store email addresses is full.");
 	       Str_Concat (StrAddresses,",",sizeof (StrAddresses) - 1);
 	      }
 	    LengthStrAddr += strlen (UsrDat.Email);
 	    if (LengthStrAddr > Mai_MAX_BYTES_STR_ADDR)
-	       Lay_ShowErrorAndExit ("The space allocated to store email addresses is full.");
+	       Err_ShowErrorAndExit ("The space allocated to store email addresses is full.");
 	    Str_Concat (StrAddresses,UsrDat.Email,sizeof (StrAddresses) - 1);
 	    HTM_A_Begin ("href=\"mailto:%s?subject=%s\"",
 		         UsrDat.Email,Gbl.Hierarchy.Crs.FullName);
@@ -1697,7 +1698,7 @@ bool Mai_SendMailMsgToConfirmEmail (void)
              FileNameMail);
    ReturnCode = system (Command);
    if (ReturnCode == -1)
-      Lay_ShowErrorAndExit ("Error when running script to send email.");
+      Err_ShowErrorAndExit ("Error when running script to send email.");
 
    /***** Remove temporary file *****/
    unlink (FileNameMail);
@@ -1851,7 +1852,7 @@ void Mai_CreateFileNameMail (char FileNameMail[PATH_MAX + 1],FILE **FileMail)
    snprintf (FileNameMail,PATH_MAX + 1,"%s/%s_mail.txt",
              Cfg_PATH_OUT_PRIVATE,Gbl.UniqueNameEncrypted);
    if ((*FileMail = fopen (FileNameMail,"wb")) == NULL)
-      Lay_ShowErrorAndExit ("Can not open file to send email.");
+      Err_ShowErrorAndExit ("Can not open file to send email.");
   }
 
 /*****************************************************************************/
@@ -1941,11 +1942,11 @@ static void Mai_EditingMailDomainConstructor (void)
   {
    /***** Pointer must be NULL *****/
    if (Mai_EditingMai != NULL)
-      Lay_WrongMailDomainExit ();
+      Err_WrongMailDomainExit ();
 
    /***** Allocate memory for mail domain *****/
    if ((Mai_EditingMai = malloc (sizeof (*Mai_EditingMai))) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Reset place *****/
    Mai_EditingMai->MaiCod    = -1L;
diff --git a/swad_main.c b/swad_main.c
index 9c07fc95..80b85e05 100644
--- a/swad_main.c
+++ b/swad_main.c
@@ -35,6 +35,7 @@
 #include "swad_config.h"
 #include "swad_connected.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_firewall.h"
 #include "swad_global.h"
 #include "swad_hierarchy.h"
@@ -149,7 +150,7 @@ int main (void)
 
       /***** Check if the user have permission to execute the action *****/
       if (!Act_CheckIfIHavePermissionToExecuteAction (Gbl.Action.Act))
-	 Lay_NoPermissionExit ();
+	 Err_NoPermissionExit ();
 
       /***** Update most frequently used actions *****/
       MFU_UpdateMFUActions ();
@@ -202,7 +203,7 @@ int main (void)
      }
 
    /***** Cleanup and exit *****/
-   Lay_ShowErrorAndExit (NULL);
+   Err_ShowErrorAndExit (NULL);
 
    return 0; // Control don't reach this point. Used to avoid warning.
   }
diff --git a/swad_mark.c b/swad_mark.c
index 50b174c2..e130602b 100644
--- a/swad_mark.c
+++ b/swad_mark.c
@@ -34,6 +34,7 @@
 #include <unistd.h>		// For unlink
 
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_HTML.h"
@@ -197,11 +198,11 @@ static void Mrk_GetNumRowsHeaderAndFooter (struct MarksProperties *Marks)
 
       /* Header (row[0]) */
       if (sscanf (row[0],"%u",&(Marks->Header)) != 1)
-         Lay_WrongNumberOfRowsExit ();
+         Err_WrongNumberOfRowsExit ();
 
       /* Footer (row[1]) */
       if (sscanf (row[1],"%u",&(Marks->Footer)) != 1)
-         Lay_WrongNumberOfRowsExit ();
+         Err_WrongNumberOfRowsExit ();
      }
    else	// Unknown numbers of header and footer rows
       Marks->Header =
@@ -268,7 +269,7 @@ static void Mrk_ChangeNumRowsHeaderOrFooter (Brw_HeadOrFoot_t HeaderOrFooter)
                      NumRows);
      }
    else
-      Lay_WrongNumberOfRowsExit ();
+      Err_WrongNumberOfRowsExit ();
 
    /***** Show again the file browser *****/
    Brw_ShowAgainFileBrowserOrWorks ();
@@ -648,14 +649,14 @@ void Mrk_ShowMyMarks (void)
       snprintf (FileNameUsrMarks,sizeof (FileNameUsrMarks),"%s/%s.html",
 		Cfg_PATH_MARK_PRIVATE,Gbl.UniqueNameEncrypted);
       if ((FileUsrMarks = fopen (FileNameUsrMarks,"wb")) == NULL)
-         Lay_ShowErrorAndExit ("Can not open file for my marks.");
+         Err_ShowErrorAndExit ("Can not open file for my marks.");
 
       /***** Show my marks *****/
       if (Mrk_GetUsrMarks (FileUsrMarks,UsrDat,PathPrivate,&Marks))
         {
          fclose (FileUsrMarks);
          if ((FileUsrMarks = fopen (FileNameUsrMarks,"rb")) == NULL)
-            Lay_ShowErrorAndExit ("Can not open file with my marks.");
+            Err_ShowErrorAndExit ("Can not open file with my marks.");
 
          /* Start HTML output */
          /*  Do not write charset here.
@@ -764,11 +765,11 @@ void Mrk_GetNotifMyMarks (char SummaryStr[Ntf_MAX_BYTES_SUMMARY + 1],
 	{
 	 /* Header (row[3]) */
 	 if (sscanf (row[3],"%u",&(Marks.Header)) != 1)
-	    Lay_WrongNumberOfRowsExit ();
+	    Err_WrongNumberOfRowsExit ();
 
 	 /* Footer (row[4]) */
 	 if (sscanf (row[4],"%u",&(Marks.Footer)) != 1)
-	    Lay_WrongNumberOfRowsExit ();
+	    Err_WrongNumberOfRowsExit ();
 
 	 if (UsrDat.IDs.Num)
 	   {
@@ -822,7 +823,7 @@ void Mrk_GetNotifMyMarks (char SummaryStr[Ntf_MAX_BYTES_SUMMARY + 1],
 		  fclose (FileUsrMarks);
 		  if (asprintf (ContentStr,"<![CDATA[%s]]>",
 				Ale_GetTextOfLastAlert ()) < 0)
-		     Lay_NotEnoughMemoryExit ();
+		     Err_NotEnoughMemoryExit ();
 	          Ale_ResetAllAlerts ();
 		 }
 	      }
@@ -830,7 +831,7 @@ void Mrk_GetNotifMyMarks (char SummaryStr[Ntf_MAX_BYTES_SUMMARY + 1],
 	      {
 	       if (asprintf (ContentStr,"<![CDATA[%s]]>",
 			     "Can not open file of marks.") < 0)
-		  Lay_NotEnoughMemoryExit ();
+		  Err_NotEnoughMemoryExit ();
 	      }
 	    unlink (FileNameUsrMarks);	// File with marks is no longer necessary
 	   }
@@ -838,7 +839,7 @@ void Mrk_GetNotifMyMarks (char SummaryStr[Ntf_MAX_BYTES_SUMMARY + 1],
 	   {
 	    if (asprintf (ContentStr,"<![CDATA[%s]]>",
 		          "User's IDs not found!") < 0)
-	       Lay_NotEnoughMemoryExit ();
+	       Err_NotEnoughMemoryExit ();
 	   }
 	}
      }
diff --git a/swad_match.c b/swad_match.c
index cece9263..72a512f2 100644
--- a/swad_match.c
+++ b/swad_match.c
@@ -34,6 +34,7 @@
 
 #include "swad_database.h"
 #include "swad_date.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_game.h"
 #include "swad_global.h"
@@ -317,11 +318,11 @@ void Mch_ListMatches (struct Gam_Games *Games,
 			         " WHERE grp_users.UsrCod=%ld"
 			           " AND grp_users.GrpCod=mch_groups.GrpCod))",
 		     Gbl.Usrs.Me.UsrDat.UsrCod) < 0)
-	  Lay_NotEnoughMemoryExit ();
+	  Err_NotEnoughMemoryExit ();
       }
     else	// Gbl.Crs.Grps.WhichGrps == Grp_ALL_GROUPS
        if (asprintf (&SubQuery,"%s","") < 0)
-	  Lay_NotEnoughMemoryExit ();
+	  Err_NotEnoughMemoryExit ();
 
    /* Make query */
    NumMatches = (unsigned)
@@ -513,7 +514,7 @@ static void Mch_ListOneOrMoreMatches (struct Gam_Games *Games,
 	{
 	 /***** Build anchor string *****/
 	 if (asprintf (&Anchor,"mch_%ld",Match.MchCod) < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** First row for this match with match data ****/
 	 /* Begin first row */
@@ -708,7 +709,7 @@ static void Mch_ListOneOrMoreMatchesTimes (const struct Mch_Match *Match,unsigne
 	StartEndTime++)
      {
       if (asprintf (&Id,"mch_time_%u_%u",(unsigned) StartEndTime,UniqueId) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       HTM_TD_Begin ("id=\"%s\" class=\"%s LT COLOR%u\"",
 		    Id,
 		    Match->Status.Showing == Mch_END ? "DATE_RED" :
@@ -886,7 +887,7 @@ static void Mch_ListOneOrMoreMatchesResult (struct Gam_Games *Games,
 	 Mch_ListOneOrMoreMatchesResultTch (Games,Match);
 	 break;
       default:
-	 Lay_WrongRoleExit ();
+	 Err_WrongRoleExit ();
 	 break;
      }
 
@@ -972,7 +973,7 @@ void Mch_ToggleVisResultsMchUsr (void)
 
    /***** Check if visibility of match results can be changed *****/
    if (!Mch_CheckIfVisibilityOfResultsCanBeChanged (&Match))
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Toggle visibility of match results *****/
    Match.Status.ShowUsrResults = !Match.Status.ShowUsrResults;
@@ -1014,11 +1015,11 @@ static void Mch_GetMatchDataFromRow (MYSQL_RES *mysql_res,
    /***** Get match data *****/
    /* Code of the match (row[0]) */
    if ((Match->MchCod = Str_ConvertStrCodToLongCod (row[0])) <= 0)
-      Lay_WrongMatchExit ();
+      Err_WrongMatchExit ();
 
    /* Code of the game (row[1]) */
    if ((Match->GamCod = Str_ConvertStrCodToLongCod (row[1])) <= 0)
-      Lay_WrongGameExit ();
+      Err_WrongGameExit ();
 
    /* Get match teacher (row[2]) */
    Match->UsrCod = Str_ConvertStrCodToLongCod (row[2]);
@@ -1151,7 +1152,7 @@ void Mch_RemoveMatch (void)
 
    /***** Check if I can remove this match *****/
    if (!Mch_CheckIfICanEditThisMatch (&Match))
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Remove the match from all database tables *****/
    Mch_RemoveMatchFromAllTables (Match.MchCod);
@@ -1355,7 +1356,7 @@ void Mch_EditMatch (void)
 
    /***** Check if I can edit this match *****/
    if (!Mch_CheckIfICanEditThisMatch (&Match))
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Show current game *****/
    Gam_ShowOnlyOneGame (&Games,&Game,
@@ -1409,20 +1410,20 @@ void Mch_GetAndCheckParameters (struct Gam_Games *Games,
    /***** Get parameters *****/
    /* Get parameters of game */
    if ((Game->GamCod = Gam_GetParams (Games)) <= 0)
-      Lay_WrongGameExit ();
+      Err_WrongGameExit ();
    Grp_GetParamWhichGroups ();
    Gam_GetDataOfGameByCod (Game);
 
    /* Get match code */
    if ((Match->MchCod = Mch_GetParamMchCod ()) <= 0)
-      Lay_WrongMatchExit ();
+      Err_WrongMatchExit ();
    Mch_GetDataOfMatchByCod (Match);
 
    /***** Ensure parameters are correct *****/
    if (Game->GamCod != Match->GamCod)
-      Lay_WrongGameExit ();
+      Err_WrongGameExit ();
    if (Game->CrsCod != Gbl.Hierarchy.Crs.CrsCod)
-      Lay_WrongGameExit ();
+      Err_WrongGameExit ();
 
    /***** Initialize context *****/
    Games->GamCod = Game->GamCod;
@@ -1625,7 +1626,7 @@ void Mch_CreateNewMatch (void)
    /***** Get form parameters *****/
    /* Get match code */
    if ((GamCod = Gam_GetParamGameCod ()) < 0)
-      Lay_WrongGameExit ();
+      Err_WrongGameExit ();
 
    /* Get match title */
    Par_GetParToText ("Title",Title,Mch_MAX_BYTES_TITLE);
@@ -1662,7 +1663,7 @@ void Mch_ChangeMatch (void)
 
    /***** Check if I can update this match *****/
    if (!Mch_CheckIfICanEditThisMatch (&Match))
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Get match title and groups *****/
    /* Get match title */
@@ -1725,7 +1726,7 @@ void Mch_ResumeMatch (void)
 
    /***** Check if I have permission to resume match *****/
    if (!Mch_CheckIfICanEditThisMatch (&Match))
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Update match status in database *****/
    Mch_UpdateMatchStatusInDB (&Match);
@@ -1830,17 +1831,17 @@ static void Mch_CreateIndexes (long GamCod,long MchCod)
 
       /* Get question code (row[0]) */
       if ((Question.QstCod = Str_ConvertStrCodToLongCod (row[0])) <= 0)
-	 Lay_WrongQuestionExit ();
+	 Err_WrongQuestionExit ();
 
       /* Get question index (row[1]) */
       if ((LongNum = Str_ConvertStrCodToLongCod (row[1])) <= 0)
-	 Lay_WrongQuestionIndexExit ();
+	 Err_WrongQuestionIndexExit ();
       QstInd = (unsigned) LongNum;
 
       /* Get answer type (row[2]) */
       Question.Answer.Type = Tst_ConvertFromStrAnsTypDBToAnsTyp (row[2]);
       if (Question.Answer.Type != Tst_ANS_UNIQUE_CHOICE)
-	 Lay_WrongAnswerExit ();
+	 Err_WrongAnswerExit ();
 
       /* Get shuffle (row[3]) */
       Question.Answer.Shuffle = (row[3][0] == 'Y');
@@ -1895,7 +1896,7 @@ static void Mch_ReorderAnswer (long MchCod,unsigned QstInd,
 
       /* Get answer index (row[0]) */
       if ((LongNum = Str_ConvertStrCodToLongCod (row[0])) <= 0)
-	 Lay_WrongAnswerIndexExit ();
+	 Err_WrongAnswerIndexExit ();
       AnsInd = (unsigned) LongNum;
       snprintf (StrOneAnswer,sizeof (StrOneAnswer),"%u",AnsInd);
 
@@ -1938,7 +1939,7 @@ void Mch_GetIndexes (long MchCod,unsigned QstInd,
 		 	 MchCod,
 			 QstInd);
    if (!StrIndexesOneQst[0])
-      Lay_ShowErrorAndExit ("No indexes found for a question.");
+      Err_ShowErrorAndExit ("No indexes found for a question.");
 
    /***** Get indexes from string *****/
    TstPrn_GetIndexesFromStr (StrIndexesOneQst,Indexes);
@@ -2009,12 +2010,12 @@ static void Mch_UpdateMatchStatusInDB (const struct Mch_Match *Match)
    if (Match->Status.Playing)	// Match is being played
      {
       if (asprintf (&MchSubQuery,"mch_matches.EndTime=NOW(),") < 0)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
      }
    else				// Match is paused, not being played
      {
       if (asprintf (&MchSubQuery,"%s","") < 0)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
      }
 
    /***** Update match status in database *****/
@@ -2482,7 +2483,7 @@ static void Mch_ShowMatchStatusForStd (struct Mch_Match *Match,Mch_Update_t Upda
    /***** Can I play this match? *****/
    ICanPlayThisMatchBasedOnGrps = Mch_CheckIfICanPlayThisMatchBasedOnGrps (Match);
    if (!ICanPlayThisMatchBasedOnGrps)
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Get student's answer to this question
 	  (<0 ==> no answer) *****/
@@ -2811,7 +2812,7 @@ static void Mch_PutFormCountdown (struct Mch_Match *Match,long Seconds,const cha
 			      " return false;",	// return false is necessary to not submit form
 		    Act_GetActCod (ActMchCntDwn),Gbl.Session.Id,
 		    Match->MchCod,Seconds) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       Frm_BeginFormOnSubmit (ActUnk,OnSubmit);
      }
 
@@ -3274,7 +3275,7 @@ static void Mch_ShowQuestionAndAnswersTch (const struct Mch_Match *Match)
       /***** Show question *****/
       /* Check answer type */
       if (Question.Answer.Type != Tst_ANS_UNIQUE_CHOICE)
-	 Lay_WrongAnswerExit ();
+	 Err_WrongAnswerExit ();
 
       /* Begin container */
       HTM_DIV_Begin ("class=\"MCH_BOTTOM\"");	// Bottom
@@ -3472,7 +3473,7 @@ static bool Mch_ShowQuestionAndAnswersStd (const struct Mch_Match *Match,
 		    Update == Mch_CHANGE_STATUS_BY_STUDENT ? " MCH_STD_ANSWER_SELECTED" :
 							     "",
 		    'A' + (char) NumOpt) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       HTM_BUTTON_OnMouseDown_Begin (NULL,Class);
       HTM_TxtF ("%c",'a' + (char) NumOpt);
       HTM_BUTTON_End ();
@@ -3684,7 +3685,7 @@ static void Mch_DrawScoreRow (double Score,double MinScore,double MaxScore,
    /* Draw bar and write number of users for this score */
    HTM_TD_Begin ("class=\"MCH_SCO_NUM%s\"",Mch_GetClassBorder (NumRow));
    if (asprintf (&Icon,"score%u_1x1.png",Color) < 0)	// Background
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    HTM_IMG (Cfg_URL_ICON_PUBLIC,Icon,
 	    Str_BuildStringLongStr ((long) NumUsrs,
 				    NumUsrs == 1 ? Txt_ROLES_SINGUL_abc[Rol_STD][Usr_SEX_UNKNOWN] :
@@ -3728,7 +3729,7 @@ static unsigned Mch_GetParamNumOpt (void)
 
    NumOpt = Par_GetParToLong ("NumOpt");
    if (NumOpt < 0)
-      Lay_ShowErrorAndExit ("Wrong number of option.");
+      Err_ShowErrorAndExit ("Wrong number of option.");
 
    return (unsigned) NumOpt;
   }
@@ -3921,7 +3922,7 @@ void Mch_GetMatchBeingPlayed (void)
 
    /***** Get match code ****/
    if ((MchCodBeingPlayed = Mch_GetParamMchCod ()) <= 0)
-      Lay_WrongMatchExit ();
+      Err_WrongMatchExit ();
 
    Mch_SetMchCodBeingPlayed (MchCodBeingPlayed);
   }
@@ -4145,11 +4146,11 @@ void Mch_GetQstAnsFromDB (long MchCod,long UsrCod,unsigned QstInd,
 
       /***** Get number of option index (row[0]) *****/
       if (sscanf (row[0],"%d",&(UsrAnswer->NumOpt)) != 1)
-	 Lay_ShowErrorAndExit ("Error when getting student's answer to a match question.");
+	 Err_ShowErrorAndExit ("Error when getting student's answer to a match question.");
 
       /***** Get answer index (row[1]) *****/
       if (sscanf (row[1],"%d",&(UsrAnswer->AnsInd)) != 1)
-	 Lay_ShowErrorAndExit ("Error when getting student's answer to a match question.");
+	 Err_ShowErrorAndExit ("Error when getting student's answer to a match question.");
      }
 
    /***** Free structure that stores the query result *****/
@@ -4314,11 +4315,11 @@ void Mch_GetMatchQuestionsFromDB (struct MchPrn_Print *Print)
 
       /* Get question code (row[0]) */
       if ((Print->PrintedQuestions[NumQst].QstCod = Str_ConvertStrCodToLongCod (row[0])) < 0)
-	 Lay_WrongQuestionExit ();
+	 Err_WrongQuestionExit ();
 
       /* Get question index (row[1]) */
       if ((LongNum = Str_ConvertStrCodToLongCod (row[1])) < 0)
-	 Lay_WrongQuestionExit ();
+	 Err_WrongQuestionExit ();
       QstInd = (unsigned) LongNum;
 
       /* Get indexes for this question (row[2]) */
diff --git a/swad_match_result.c b/swad_match_result.c
index 2d7e8f3a..b9b723c0 100644
--- a/swad_match_result.c
+++ b/swad_match_result.c
@@ -35,6 +35,7 @@
 #include "swad_action.h"
 #include "swad_database.h"
 #include "swad_date.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_HTML.h"
@@ -169,7 +170,7 @@ void MchRes_ShowMyMchResultsInGam (void)
 
    /***** Get parameters *****/
    if ((Game.GamCod = Gam_GetParams (&Games)) <= 0)
-      Lay_WrongGameExit ();
+      Err_WrongGameExit ();
    Gam_GetDataOfGameByCod (&Game);
 
    /***** Game begin *****/
@@ -219,9 +220,9 @@ void MchRes_ShowMyMchResultsInMch (void)
 
    /***** Get parameters *****/
    if ((Game.GamCod = Gam_GetParams (&Games)) <= 0)
-      Lay_WrongGameExit ();
+      Err_WrongGameExit ();
    if ((Match.MchCod = Mch_GetParamMchCod ()) <= 0)
-      Lay_WrongMatchExit ();
+      Err_WrongMatchExit ();
    Gam_GetDataOfGameByCod (&Game);
    Mch_GetDataOfMatchByCod (&Match);
 
@@ -373,7 +374,7 @@ void MchRes_ShowAllMchResultsInGam (void)
 
    /***** Get parameters *****/
    if ((Game.GamCod = Gam_GetParams (&Games)) <= 0)
-      Lay_WrongGameExit ();
+      Err_WrongGameExit ();
    Gam_GetDataOfGameByCod (&Game);
 
    /***** Game begin *****/
@@ -462,9 +463,9 @@ void MchRes_ShowAllMchResultsInMch (void)
 
    /***** Get parameters *****/
    if ((Game.GamCod = Gam_GetParams (&Games)) <= 0)
-      Lay_WrongGameExit ();
+      Err_WrongGameExit ();
    if ((Match.MchCod = Mch_GetParamMchCod ()) <= 0)
-      Lay_WrongMatchExit ();
+      Err_WrongMatchExit ();
    Gam_GetDataOfGameByCod (&Game);
    Mch_GetDataOfMatchByCod (&Match);
 
@@ -734,7 +735,7 @@ static void MchRes_BuildGamesSelectedCommas (struct Gam_Games *Games,
    /***** Allocate memory for subquery of games selected *****/
    MaxLength = (size_t) Games->NumSelected * (Cns_MAX_DECIMAL_DIGITS_LONG + 1);
    if ((*GamesSelectedCommas = malloc (MaxLength + 1)) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Build subquery with list of selected games *****/
    (*GamesSelectedCommas)[0] = '\0';
@@ -795,19 +796,19 @@ static void MchRes_ShowMchResults (struct Gam_Games *Games,
    if (MchCod > 0)
      {
       if (asprintf (&MchSubQuery," AND mch_results.MchCod=%ld",MchCod) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
      }
    else
      {
       if (asprintf (&MchSubQuery,"%s","") < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
      }
 
    /***** Build games subquery *****/
    if (GamCod > 0)
      {
       if (asprintf (&GamSubQuery," AND mch_matches.GamCod=%ld",GamCod) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
      }
    else if (GamesSelectedCommas)
      {
@@ -815,18 +816,18 @@ static void MchRes_ShowMchResults (struct Gam_Games *Games,
 	{
 	 if (asprintf (&GamSubQuery," AND mch_matches.GamCod IN (%s)",
 		       GamesSelectedCommas) < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 	}
       else
 	{
 	 if (asprintf (&GamSubQuery,"%s","") < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 	}
      }
    else
      {
       if (asprintf (&GamSubQuery,"%s","") < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
      }
 
    /***** Subquery: get hidden games?
@@ -837,11 +838,11 @@ static void MchRes_ShowMchResults (struct Gam_Games *Games,
      {
       case Usr_ME:	// A student watching her/his results
          if (asprintf (&HidGamSubQuery," AND gam_games.Hidden='N'") < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 	 break;
       default:		// A teacher/admin watching the results of other users
 	 if (asprintf (&HidGamSubQuery,"%s","") < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 	 break;
      }
 
@@ -883,7 +884,7 @@ static void MchRes_ShowMchResults (struct Gam_Games *Games,
 	 /* Get match code */
          MchPrn_ResetPrint (&Print);
 	 if ((Print.MchCod = DB_GetNextCode (mysql_res)) < 0)
-	    Lay_WrongMatchExit ();
+	    Err_WrongMatchExit ();
 
 	 /* Get match result data */
 	 Print.UsrCod = UsrDat->UsrCod;
@@ -908,7 +909,7 @@ static void MchRes_ShowMchResults (struct Gam_Games *Games,
 	   {
 	    UniqueId++;
 	    if (asprintf (&Id,"mch_res_time_%u_%u",(unsigned) StartEndTime,UniqueId) < 0)
-	       Lay_NotEnoughMemoryExit ();
+	       Err_NotEnoughMemoryExit ();
 	    HTM_TD_Begin ("id =\"%s\" class=\"DAT LT COLOR%u\"",
 			  Id,Gbl.RowEvenOdd);
 	    Dat_WriteLocalDateHMSFromUTC (Id,Print.TimeUTC[StartEndTime],
@@ -1213,9 +1214,9 @@ void MchRes_ShowOneMchResult (void)
 	    if (!Usr_ChkUsrCodAndGetAllUsrDataFromUsrCod (UsrDat,
 	                                                  Usr_DONT_GET_PREFS,
 	                                                  Usr_DONT_GET_ROLE_IN_CURRENT_CRS))
-               Lay_WrongUserExit ();
+               Err_WrongUserExit ();
 	    if (!Usr_CheckIfICanViewTstExaMchResult (UsrDat))
-	       Lay_NoPermissionExit ();
+	       Err_NoPermissionExit ();
 
 	    /* User */
 	    HTM_TR_Begin (NULL);
@@ -1249,7 +1250,7 @@ void MchRes_ShowOneMchResult (void)
 		  HTM_TD_End ();
 
 		  if (asprintf (&Id,"match_%u",(unsigned) StartEndTime) < 0)
-		     Lay_NotEnoughMemoryExit ();
+		     Err_NotEnoughMemoryExit ();
 		  HTM_TD_Begin ("id=\"%s\" class=\"DAT LB\"",Id);
 		     Dat_WriteLocalDateHMSFromUTC (Id,Print.TimeUTC[StartEndTime],
 						   Gbl.Prefs.DateFormat,Dat_SEPARATOR_COMMA,
@@ -1355,7 +1356,7 @@ void MchRes_ShowOneMchResult (void)
       Box_BoxEnd ();
      }
    else	// I am not allowed to view this match result
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
   }
 
 /*****************************************************************************/
diff --git a/swad_media.c b/swad_media.c
index 31c6b27c..a269dd1e 100644
--- a/swad_media.c
+++ b/swad_media.c
@@ -40,6 +40,7 @@
 #include "swad_config.h"
 #include "swad_cookie.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_file.h"
 #include "swad_file_browser.h"
 #include "swad_form.h"
@@ -308,7 +309,7 @@ void Med_GetMediaDataByCod (struct Med_Media *Media)
 	     Length = Cns_MAX_BYTES_WWW;
 
 	 if ((Media->URL = malloc (Length + 1)) == NULL)
-            Lay_NotEnoughMemoryExit ();
+            Err_NotEnoughMemoryExit ();
 	 Str_Copy (Media->URL,row[2],Length);
 	}
 
@@ -324,12 +325,12 @@ void Med_GetMediaDataByCod (struct Med_Media *Media)
 	     Length = Med_MAX_BYTES_TITLE;
 
 	 if ((Media->Title = malloc (Length + 1)) == NULL)
-            Lay_NotEnoughMemoryExit ();
+            Err_NotEnoughMemoryExit ();
 	 Str_Copy (Media->Title,row[3],Length);
 	}
      }
    else
-      Lay_ShowErrorAndExit ("Internal error in database when getting media data.");
+      Err_ShowErrorAndExit ("Internal error in database when getting media data.");
 
    /***** Free structure that stores the query result *****/
    DB_FreeMySQLResult (&mysql_res);
@@ -496,7 +497,7 @@ static void Med_PutHiddenFormTypeMediaUploader (const char UniqueId[Frm_MAX_BYTE
 
    /***** Hidden field with form type *****/
    if (asprintf (&Id,"%s_%s",UniqueId,MediaUploader->ParamSuffix) < 0)	// <id>_ParamSuffix
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    Par_PutHiddenParamUnsignedDisabled (Id,ParamUploadMedia->FormType,
 			               (unsigned) MediaUploader->FormType);
    free (Id);
@@ -662,7 +663,7 @@ static void Usr_GetURLFromForm (const char *ParamName,struct Med_Media *Media)
          with the URL coming from the form */
       Med_FreeMediaURL (Media);
       if ((Media->URL = malloc (Length + 1)) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
       Str_Copy (Media->URL,URL,Length);
      }
   }
@@ -686,7 +687,7 @@ static void Usr_GetTitleFromForm (const char *ParamName,struct Med_Media *Media)
          with the title coming from the form */
       Med_FreeMediaTitle (Media);
       if ((Media->Title = malloc (Length + 1)) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
       Str_Copy (Media->Title,Title,Length);
      }
   }
@@ -983,7 +984,7 @@ static int Med_ResizeImage (struct Med_Media *Media,
              PathFileProcessed);
    ReturnCode = system (Command);
    if (ReturnCode == -1)
-      Lay_ShowErrorAndExit ("Error when running command to process media.");
+      Err_ShowErrorAndExit ("Error when running command to process media.");
 
    ReturnCode = WEXITSTATUS(ReturnCode);
    return ReturnCode;
@@ -1006,7 +1007,7 @@ static int Med_GetFirstFrame (const char PathFileOriginal[PATH_MAX + 1],
              PathFileProcessed);
    ReturnCode = system (Command);
    if (ReturnCode == -1)
-      Lay_ShowErrorAndExit ("Error when running command to process media.");
+      Err_ShowErrorAndExit ("Error when running command to process media.");
 
    ReturnCode = WEXITSTATUS(ReturnCode);
 
@@ -1501,7 +1502,7 @@ static void Med_ShowJPG (const struct Med_Media *Media,
 	     Media->Name,Med_Extensions[Med_JPG]);
    if (asprintf (&FullPathJPGPriv,"%s/%s",
 	         PathMedPriv,FileNameJPG) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Check if private media file exists *****/
    if (Fil_CheckIfPathExists (FullPathJPGPriv))
@@ -1524,7 +1525,7 @@ static void Med_ShowJPG (const struct Med_Media *Media,
       /***** Show media *****/
       if (asprintf (&URL,"%s/%s",
 		    Cfg_URL_FILE_BROWSER_TMP_PUBLIC,TmpPubDir) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       HTM_IMG (URL,FileNameJPG,Media->Title,
 	       "class=\"%s\" lazyload=\"on\"",ClassMedia);	// Lazy load of the media
       free (URL);
@@ -1559,13 +1560,13 @@ static void Med_ShowGIF (const struct Med_Media *Media,
 	     Media->Name,Med_Extensions[Med_GIF]);
    if (asprintf (&FullPathGIFPriv,"%s/%s",	// The animated GIF image
 		 PathMedPriv,FileNameGIF) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Build private path to static PNG image *****/
    snprintf (FileNamePNG,sizeof (FileNamePNG),"%s.png",Media->Name);
    if (asprintf (&FullPathPNGPriv,"%s/%s",
 		 PathMedPriv,FileNamePNG) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Check if private media file exists *****/
    if (Fil_CheckIfPathExists (FullPathGIFPriv))		// The animated GIF image
@@ -1589,11 +1590,11 @@ static void Med_ShowGIF (const struct Med_Media *Media,
       /***** Create URLs pointing to symbolic links *****/
       if (asprintf (&URL,"%s/%s",
 		    Cfg_URL_FILE_BROWSER_TMP_PUBLIC,TmpPubDir) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       if (asprintf (&URL_GIF,"%s/%s",URL,FileNameGIF) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       if (asprintf (&URL_PNG,"%s/%s",URL,FileNamePNG) < 0)	// The static PNG image
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
 
       /***** Check if private media file exists *****/
       if (Fil_CheckIfPathExists (FullPathPNGPriv))		// The static PNG image
@@ -1651,7 +1652,7 @@ static void Med_ShowVideo (const struct Med_Media *Media,
 	     Media->Name,Med_Extensions[Media->Type]);
    if (asprintf (&FullPathVideoPriv,"%s/%s",
 	         PathMedPriv,FileNameVideo) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Check if private media file exists *****/
    if (Fil_CheckIfPathExists (FullPathVideoPriv))
@@ -1674,7 +1675,7 @@ static void Med_ShowVideo (const struct Med_Media *Media,
       /***** Create URL pointing to symbolic link *****/
       if (asprintf (&URL,"%s/%s",
 		    Cfg_URL_FILE_BROWSER_TMP_PUBLIC,TmpPubDir) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
 
       /***** Show media *****/
       HTM_TxtF ("<video src=\"%s/%s\""
@@ -1847,7 +1848,7 @@ long Med_CloneMedia (const struct Med_Media *MediaSrc)
       if (Length > Cns_MAX_BYTES_WWW)
 	  Length = Cns_MAX_BYTES_WWW;
       if ((MediaDst.URL = malloc (Length + 1)) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
       Str_Copy (MediaDst.URL,MediaSrc->URL,Length);
      }
 
@@ -1860,7 +1861,7 @@ long Med_CloneMedia (const struct Med_Media *MediaSrc)
       if (Length > Cns_MAX_BYTES_WWW)
 	  Length = Cns_MAX_BYTES_WWW;
       if ((MediaDst.Title = malloc (Length + 1)) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
       Str_Copy (MediaDst.Title,MediaSrc->Title,Length);
      }
 
@@ -1994,7 +1995,7 @@ void Med_RemoveMedia (long MedCod)
 		  /***** Remove private JPG file *****/
 		  if (asprintf (&FullPathMediaPriv,"%s/%s.%s",
 			        PathMedPriv,Media.Name,Med_Extensions[Med_JPG]) < 0)
-		     Lay_NotEnoughMemoryExit ();
+		     Err_NotEnoughMemoryExit ();
 		  unlink (FullPathMediaPriv);
                   free (FullPathMediaPriv);
 		  break;
@@ -2002,14 +2003,14 @@ void Med_RemoveMedia (long MedCod)
 		  /***** Remove private GIF file *****/
 		  if (asprintf (&FullPathMediaPriv,"%s/%s.%s",
 			        PathMedPriv,Media.Name,Med_Extensions[Med_GIF]) < 0)
-		     Lay_NotEnoughMemoryExit ();
+		     Err_NotEnoughMemoryExit ();
 		  unlink (FullPathMediaPriv);
                   free (FullPathMediaPriv);
 
 		  /***** Remove private PNG file *****/
 		  if (asprintf (&FullPathMediaPriv,"%s/%s.png",
 			        PathMedPriv,Media.Name) < 0)
-		     Lay_NotEnoughMemoryExit ();
+		     Err_NotEnoughMemoryExit ();
 		  unlink (FullPathMediaPriv);
                   free (FullPathMediaPriv);
 
@@ -2020,7 +2021,7 @@ void Med_RemoveMedia (long MedCod)
 		  /***** Remove private video file *****/
 		  if (asprintf (&FullPathMediaPriv,"%s/%s.%s",
 			        PathMedPriv,Media.Name,Med_Extensions[Media.Type]) < 0)
-		     Lay_NotEnoughMemoryExit ();
+		     Err_NotEnoughMemoryExit ();
 		  unlink (FullPathMediaPriv);
 		  free (FullPathMediaPriv);
 
diff --git a/swad_message.c b/swad_message.c
index cb70a9da..c37feded 100644
--- a/swad_message.c
+++ b/swad_message.c
@@ -38,6 +38,7 @@
 #include "swad_config.h"
 #include "swad_course.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_figure.h"
 #include "swad_form.h"
 #include "swad_forum.h"
@@ -257,7 +258,7 @@ static void Msg_PutFormMsgUsrs (struct Msg_Messages *Messages,
    if ((Messages->Reply.IsReply = Par_GetParToBool ("IsReply")))
       /* Get original message code */
       if ((Messages->Reply.OriginalMsgCod = Msg_GetParamMsgCod ()) <= 0)
-         Lay_WrongMessageExit ();
+         Err_WrongMessageExit ();
 
    /***** Get user's code of possible preselected recipient *****/
    if (Usr_GetParamOtherUsrCodEncryptedAndGetUsrData ())	// There is a preselected recipient
@@ -620,7 +621,7 @@ static void Msg_WriteFormSubjectAndContentMsgToUsrs (struct Msg_Messages *Messag
 			      " FROM msg_content"
 			     " WHERE MsgCod=%ld",
 			     MsgCod) != 1)
-	    Lay_WrongMessageExit ();
+	    Err_WrongMessageExit ();
 
 	 row = mysql_fetch_row (mysql_res);
 
@@ -770,7 +771,7 @@ void Msg_RecMsgFromUsr (void)
    if ((IsReply = Par_GetParToBool ("IsReply")))
       /* Get original message code */
       if ((OriginalMsgCod = Msg_GetParamMsgCod ()) <= 0)
-         Lay_WrongMessageExit ();
+         Err_WrongMessageExit ();
 
    /* Get user's code of possible preselected recipient */
    Usr_GetParamOtherUsrCodEncryptedAndGetListIDs ();
@@ -1197,7 +1198,7 @@ void Msg_DelSntMsg (void)
 
    /***** Get the code of the message to delete *****/
    if ((MsgCod = Msg_GetParamMsgCod ()) <= 0)
-      Lay_WrongMessageExit ();
+      Err_WrongMessageExit ();
 
    /***** Delete the message *****/
    /* Delete the sent message */
@@ -1219,7 +1220,7 @@ void Msg_DelRecMsg (void)
 
    /***** Get the code of the message to delete *****/
    if ((MsgCod = Msg_GetParamMsgCod ()) <= 0)
-      Lay_WrongMessageExit ();
+      Err_WrongMessageExit ();
 
    /***** Delete the message *****/
    /* Delete the received message */
@@ -1243,7 +1244,7 @@ void Msg_ExpSntMsg (void)
 
    /***** Get the code of the message to expand *****/
    if ((Messages.ExpandedMsgCod = Msg_GetParamMsgCod ()) <= 0)
-      Lay_WrongMessageExit ();
+      Err_WrongMessageExit ();
 
    /***** Expand the message *****/
    Msg_ExpandSentMsg (Messages.ExpandedMsgCod);
@@ -1265,7 +1266,7 @@ void Msg_ExpRecMsg (void)
 
    /***** Get the code of the message to expand *****/
    if ((Messages.ExpandedMsgCod = Msg_GetParamMsgCod ()) <= 0)
-      Lay_WrongMessageExit ();
+      Err_WrongMessageExit ();
 
    /***** Expand the message *****/
    Msg_ExpandReceivedMsg (Messages.ExpandedMsgCod);
@@ -1289,7 +1290,7 @@ void Msg_ConSntMsg (void)
 
    /***** Get the code of the message to contract *****/
    if ((MsgCod = Msg_GetParamMsgCod ()) <= 0)
-      Lay_WrongMessageExit ();
+      Err_WrongMessageExit ();
 
    /***** Contract the message *****/
    Msg_ContractSentMsg (MsgCod);
@@ -1308,7 +1309,7 @@ void Msg_ConRecMsg (void)
 
    /***** Get the code of the message to contract *****/
    if ((MsgCod = Msg_GetParamMsgCod ()) <= 0)
-      Lay_WrongMessageExit ();
+      Err_WrongMessageExit ();
 
    /***** Contract the message *****/
    Msg_ContractReceivedMsg (MsgCod);
@@ -1481,7 +1482,7 @@ static unsigned long Msg_DelSomeRecOrSntMsgsUsr (const struct Msg_Messages *Mess
 	NumMsg++)
      {
       if ((MsgCod = DB_GetNextCode (mysql_res)) <= 0)
-         Lay_WrongMessageExit ();
+         Err_WrongMessageExit ();
 
       switch (Messages->TypeOfMessages)
         {
@@ -1777,7 +1778,7 @@ static unsigned Msg_GetNumUnreadMsgs (const struct Msg_Messages *Messages,
 		       Gbl.Usrs.Me.UsrDat.UsrCod,
 		       Messages->FilterCrsCod,
 		       FilterFromToSubquery) < 0)
-            Lay_NotEnoughMemoryExit ();
+            Err_NotEnoughMemoryExit ();
 	}
       else
         {
@@ -1790,7 +1791,7 @@ static unsigned Msg_GetNumUnreadMsgs (const struct Msg_Messages *Messages,
 				   " AND msg_snt.CrsCod=%ld",
 			Gbl.Usrs.Me.UsrDat.UsrCod,
 			Messages->FilterCrsCod) < 0)
-            Lay_NotEnoughMemoryExit ();
+            Err_NotEnoughMemoryExit ();
         }
      }
    else	// If no origin course selected
@@ -1805,7 +1806,7 @@ static unsigned Msg_GetNumUnreadMsgs (const struct Msg_Messages *Messages,
 				   " AND msg_snt.UsrCod=usr_data.UsrCod%s",
 			Gbl.Usrs.Me.UsrDat.UsrCod,
 			FilterFromToSubquery) < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
         }
       else
 	{
@@ -1814,7 +1815,7 @@ static unsigned Msg_GetNumUnreadMsgs (const struct Msg_Messages *Messages,
 			         " WHERE UsrCod=%ld"
 			           " AND Open='N'",
 		        Gbl.Usrs.Me.UsrDat.UsrCod) < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
         }
      }
 
@@ -2010,7 +2011,7 @@ static void Msg_ShowSentOrReceivedMessages (struct Msg_Messages *Messages)
            {
             row = mysql_fetch_row (mysql_res);
             if (sscanf (row[0],"%ld",&MsgCod) != 1)
-               Lay_WrongMessageExit ();
+               Err_WrongMessageExit ();
 
             if (MsgCod == Messages->ExpandedMsgCod)	// Expanded message found
               {
@@ -2045,7 +2046,7 @@ static void Msg_ShowSentOrReceivedMessages (struct Msg_Messages *Messages)
          row = mysql_fetch_row (mysql_res);
 
          if (sscanf (row[0],"%ld",&MsgCod) != 1)
-            Lay_WrongMessageExit ();
+            Err_WrongMessageExit ();
          NumMsg = NumRows - NumRow + 1;
          Msg_ShowASentOrReceivedMessage (Messages,NumMsg,MsgCod);
         }
@@ -2133,7 +2134,7 @@ static unsigned Msg_GetSentOrReceivedMsgs (const struct Msg_Messages *Messages,
 				          " AND msg_snt_deleted.UsrCod=usr_data.UsrCod%s)",
 			     UsrCod,StrUnreadMsg,Messages->FilterCrsCod,FilterFromToSubquery,
 			     UsrCod,StrUnreadMsg,Messages->FilterCrsCod,FilterFromToSubquery) < 0)
-                  Lay_NotEnoughMemoryExit ();
+                  Err_NotEnoughMemoryExit ();
               }
             else
               {
@@ -2154,7 +2155,7 @@ static unsigned Msg_GetSentOrReceivedMsgs (const struct Msg_Messages *Messages,
 				          " AND msg_snt_deleted.CrsCod=%ld)",
 			     UsrCod,StrUnreadMsg,Messages->FilterCrsCod,
 			     UsrCod,StrUnreadMsg,Messages->FilterCrsCod) < 0)
-                  Lay_NotEnoughMemoryExit ();
+                  Err_NotEnoughMemoryExit ();
               }
             break;
          case Msg_SENT:
@@ -2181,7 +2182,7 @@ static unsigned Msg_GetSentOrReceivedMsgs (const struct Msg_Messages *Messages,
 				          "%s)",
 			     UsrCod,Messages->FilterCrsCod,FilterFromToSubquery,
 			     UsrCod,Messages->FilterCrsCod,FilterFromToSubquery) < 0)
-                  Lay_NotEnoughMemoryExit ();
+                  Err_NotEnoughMemoryExit ();
               }
             else
               {
@@ -2190,7 +2191,7 @@ static unsigned Msg_GetSentOrReceivedMsgs (const struct Msg_Messages *Messages,
 				       " WHERE UsrCod=%ld"
 				         " AND CrsCod=%ld",
 			     UsrCod,Messages->FilterCrsCod) < 0)
-                  Lay_NotEnoughMemoryExit ();
+                  Err_NotEnoughMemoryExit ();
               }
             break;
          default: // Not aplicable here
@@ -2225,7 +2226,7 @@ static unsigned Msg_GetSentOrReceivedMsgs (const struct Msg_Messages *Messages,
 				          "%s)",
 			     UsrCod,StrUnreadMsg,FilterFromToSubquery,
 			     UsrCod,StrUnreadMsg,FilterFromToSubquery) < 0)
-                  Lay_NotEnoughMemoryExit ();
+                  Err_NotEnoughMemoryExit ();
               }
             else
               {
@@ -2236,7 +2237,7 @@ static unsigned Msg_GetSentOrReceivedMsgs (const struct Msg_Messages *Messages,
 				       " WHERE UsrCod=%ld"
 				          "%s",
 			     UsrCod,StrUnreadMsg) < 0)
-                  Lay_NotEnoughMemoryExit ();
+                  Err_NotEnoughMemoryExit ();
               }
             break;
          case Msg_SENT:
@@ -2259,7 +2260,7 @@ static unsigned Msg_GetSentOrReceivedMsgs (const struct Msg_Messages *Messages,
 				          " AND msg_rcv_deleted.UsrCod=usr_data.UsrCod%s)",
 			     UsrCod,FilterFromToSubquery,
 			     UsrCod,FilterFromToSubquery) < 0)
-                  Lay_NotEnoughMemoryExit ();
+                  Err_NotEnoughMemoryExit ();
               }
             else
               {
@@ -2267,7 +2268,7 @@ static unsigned Msg_GetSentOrReceivedMsgs (const struct Msg_Messages *Messages,
 				        " FROM msg_snt"
 				       " WHERE UsrCod=%ld",
                              UsrCod) < 0)
-                  Lay_NotEnoughMemoryExit ();
+                  Err_NotEnoughMemoryExit ();
               }
             break;
          default: // Not aplicable here
@@ -2720,12 +2721,12 @@ static void Msg_SetNumMsgsStr (const struct Msg_Messages *Messages,
 	      {
 	       if (asprintf (NumMsgsStr,"1 %s, 1 %s",
 			     Txt_message_received,Txt_unread_MESSAGE) < 0)
-                  Lay_NotEnoughMemoryExit ();
+                  Err_NotEnoughMemoryExit ();
 	      }
 	    else
 	      {
 	       if (asprintf (NumMsgsStr,"1 %s",Txt_message_received) < 0)
-                  Lay_NotEnoughMemoryExit ();
+                  Err_NotEnoughMemoryExit ();
 	      }
 	   }
 	 else
@@ -2734,21 +2735,21 @@ static void Msg_SetNumMsgsStr (const struct Msg_Messages *Messages,
 	      {
 	       if (asprintf (NumMsgsStr,"%u %s",
 			     Messages->NumMsgs,Txt_messages_received) < 0)
-                  Lay_NotEnoughMemoryExit ();
+                  Err_NotEnoughMemoryExit ();
 	      }
 	    else if (NumUnreadMsgs == 1)
 	      {
 	       if (asprintf (NumMsgsStr,"%u %s, 1 %s",
 			     Messages->NumMsgs,Txt_messages_received,
 			     Txt_unread_MESSAGE) < 0)
-                  Lay_NotEnoughMemoryExit ();
+                  Err_NotEnoughMemoryExit ();
 	      }
 	    else
 	      {
 	       if (asprintf (NumMsgsStr,"%u %s, %u %s",
 			     Messages->NumMsgs,Txt_messages_received,
 			     NumUnreadMsgs,Txt_unread_MESSAGES) < 0)
-                  Lay_NotEnoughMemoryExit ();
+                  Err_NotEnoughMemoryExit ();
 	      }
 	   }
 	 break;
@@ -2756,13 +2757,13 @@ static void Msg_SetNumMsgsStr (const struct Msg_Messages *Messages,
 	 if (Messages->NumMsgs == 1)
 	   {
 	    if (asprintf (NumMsgsStr,"1 %s",Txt_message_sent) < 0)
-               Lay_NotEnoughMemoryExit ();
+               Err_NotEnoughMemoryExit ();
 	   }
 	 else
 	   {
 	    if (asprintf (NumMsgsStr,"%u %s",
 			  Messages->NumMsgs,Txt_messages_sent) < 0)
-               Lay_NotEnoughMemoryExit ();
+               Err_NotEnoughMemoryExit ();
 	   }
 	 break;
       default:
@@ -3105,7 +3106,7 @@ static void Msg_GetMsgSntData (long MsgCod,long *CrsCod,long *UsrCod,
 
    /* Result should have a unique row */
    if (NumRows != 1)
-      Lay_WrongMessageExit ();
+      Err_WrongMessageExit ();
 
    /* Get number of rows */
    row = mysql_fetch_row (mysql_res);
@@ -3158,7 +3159,7 @@ static void Msg_GetMsgContent (long MsgCod,char Content[Cns_MAX_BYTES_LONG_TEXT
 			      " FROM msg_content"
 			     " WHERE MsgCod=%ld",
 			     MsgCod) != 1)
-      Lay_WrongMessageExit ();
+      Err_WrongMessageExit ();
 
    /***** Get number of rows *****/
    row = mysql_fetch_row (mysql_res);
@@ -3216,7 +3217,7 @@ static void Msg_GetStatusOfReceivedMsg (long MsgCod,bool *Open,bool *Replied,boo
 			 " AND UsrCod=%ld",
 		       MsgCod,
 		       Gbl.Usrs.Me.UsrDat.UsrCod) != 1)
-      Lay_ShowErrorAndExit ("Error when getting if a received message has been replied/expanded.");
+      Err_ShowErrorAndExit ("Error when getting if a received message has been replied/expanded.");
 
    /***** Get number of rows *****/
    row = mysql_fetch_row (mysql_res);
@@ -3461,7 +3462,7 @@ void Msg_GetNotifMessage (char SummaryStr[Ntf_MAX_BYTES_SUMMARY + 1],
 	{
 	 Length = strlen (row[1]);
 	 if ((*ContentStr = malloc (Length + 1)) == NULL)
-            Lay_NotEnoughMemoryExit ();
+            Err_NotEnoughMemoryExit ();
 	 Str_Copy (*ContentStr,row[1],Length);
 	}
      }
@@ -3949,7 +3950,7 @@ void Msg_WriteMsgDate (time_t TimeUTC,const char *ClassBackground)
 
    UniqueId++;
    if (asprintf (&Id,"msg_date_%u",UniqueId) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Start cell *****/
    HTM_TD_Begin ("id=\"%s\" class=\"%s RT\" style=\"width:106px;\"",
@@ -4053,7 +4054,7 @@ void Msg_BanSenderWhenShowingMsgs (void)
    if (!Usr_ChkUsrCodAndGetAllUsrDataFromUsrCod (&Gbl.Usrs.Other.UsrDat,
                                                  Usr_DONT_GET_PREFS,
                                                  Usr_DONT_GET_ROLE_IN_CURRENT_CRS))
-      Lay_WrongUserExit ();
+      Err_WrongUserExit ();
 
    /***** Insert pair (sender's code - my code) in table of banned senders if not inserted *****/
    DB_QueryREPLACE ("can not ban sender",
@@ -4113,7 +4114,7 @@ static void Msg_UnbanSender (void)
    if (!Usr_ChkUsrCodAndGetAllUsrDataFromUsrCod (&Gbl.Usrs.Other.UsrDat,
                                                  Usr_DONT_GET_PREFS,
                                                  Usr_DONT_GET_ROLE_IN_CURRENT_CRS))
-      Lay_WrongUserExit ();
+      Err_WrongUserExit ();
 
    /***** Remove pair (sender's code - my code) from table of banned senders *****/
    DB_QueryDELETE ("can not ban sender",
diff --git a/swad_network.c b/swad_network.c
index cc5e8e5f..75a1f14f 100644
--- a/swad_network.c
+++ b/swad_network.c
@@ -29,6 +29,7 @@
 
 #include "swad_box.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_figure.h"
 #include "swad_form.h"
 #include "swad_global.h"
@@ -534,7 +535,7 @@ void Net_ShowWebAndSocialNetworksStats (void)
 			 Gbl.Hierarchy.Crs.CrsCod);
          break;
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 break;
      }
 
@@ -571,7 +572,7 @@ void Net_ShowWebAndSocialNetworksStats (void)
 	{
 	 /* Get number of users (row[1]) */
 	 if (sscanf (row[1],"%u",&NumUsrs) != 1)
-	    Lay_ShowErrorAndExit ("Error when getting number of files.");
+	    Err_ShowErrorAndExit ("Error when getting number of files.");
 
 	 HTM_TR_Begin (NULL);
 
diff --git a/swad_notice.c b/swad_notice.c
index caf28de3..b9429f94 100644
--- a/swad_notice.c
+++ b/swad_notice.c
@@ -34,6 +34,7 @@
 
 #include "swad_box.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_figure.h"
 #include "swad_form.h"
 #include "swad_global.h"
@@ -447,7 +448,7 @@ void Not_ShowNotices (Not_Listing_t TypeNoticesListing,long HighlightNotCod)
 
       /* Get notice code (row[0]) */
       if (sscanf (row[0],"%ld",&NotCod) != 1)
-	 Lay_WrongNoticeExit ();
+	 Err_WrongNoticeExit ();
 
       /* Get creation time (row[1] holds the UTC date-time) */
       TimeUTC = Dat_GetUNIXTimeFromStr (row[1]);
@@ -720,7 +721,7 @@ static void Not_DrawANotice (Not_Listing_t TypeNoticesListing,
       HTM_BUTTON_SUBMIT_Begin (Txt_See_full_notice,"BT_LINK RT",NULL);
      }
    if (asprintf (&Id,"not_date_%u",UniqueId) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    HTM_SPAN_Begin ("id=\"%s\"",Id);
    HTM_SPAN_End ();
    if (TypeNoticesListing == Not_LIST_BRIEF_NOTICES)
@@ -825,7 +826,7 @@ void Not_GetSummaryAndContentNotice (char SummaryStr[Ntf_MAX_BYTES_SUMMARY + 1],
 	{
 	 Length = strlen (row[0]);
 	 if ((*ContentStr = malloc (Length + 1)) == NULL)
-            Lay_NotEnoughMemoryExit ();
+            Err_NotEnoughMemoryExit ();
 	 Str_Copy (*ContentStr,row[0],Length);
 	}
      }
@@ -928,20 +929,20 @@ unsigned Not_GetNumNotices (Hie_Lvl_Level_t Scope,Not_Status_t Status,unsigned *
                          Status);
          break;
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 break;
      }
 
    /***** Get number of notices *****/
    row = mysql_fetch_row (mysql_res);
    if (sscanf (row[0],"%u",&NumNotices) != 1)
-      Lay_ShowErrorAndExit ("Error when getting number of notices.");
+      Err_ShowErrorAndExit ("Error when getting number of notices.");
 
    /***** Get number of notifications by email *****/
    if (row[1])
      {
       if (sscanf (row[1],"%u",NumNotif) != 1)
-         Lay_ShowErrorAndExit ("Error when getting number of notifications of notices.");
+         Err_ShowErrorAndExit ("Error when getting number of notifications of notices.");
      }
    else
       *NumNotif = 0;
@@ -1034,20 +1035,20 @@ unsigned Not_GetNumNoticesDeleted (Hie_Lvl_Level_t Scope,unsigned *NumNotif)
                          Gbl.Hierarchy.Crs.CrsCod);
          break;
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 break;
      }
 
    /***** Get number of notices *****/
    row = mysql_fetch_row (mysql_res);
    if (sscanf (row[0],"%u",&NumNotices) != 1)
-      Lay_ShowErrorAndExit ("Error when getting number of deleted notices.");
+      Err_ShowErrorAndExit ("Error when getting number of deleted notices.");
 
    /***** Get number of notifications by email *****/
    if (row[1])
      {
       if (sscanf (row[1],"%u",NumNotif) != 1)
-         Lay_ShowErrorAndExit ("Error when getting number of notifications of deleted notices.");
+         Err_ShowErrorAndExit ("Error when getting number of notifications of deleted notices.");
      }
    else
       *NumNotif = 0;
diff --git a/swad_notification.c b/swad_notification.c
index fe9886bc..9b94f728 100644
--- a/swad_notification.c
+++ b/swad_notification.c
@@ -38,6 +38,7 @@
 #include "swad_config.h"
 #include "swad_database.h"
 #include "swad_enrolment.h"
+#include "swad_error.h"
 #include "swad_figure.h"
 #include "swad_follow.h"
 #include "swad_form.h"
@@ -455,7 +456,7 @@ void Ntf_ShowMyNotifications (void)
 
          /* Get status (row[8]) */
          if (sscanf (row[8],"%u",&Status) != 1)
-            Lay_WrongStatusExit ();
+            Err_WrongStatusExit ();
          StatusTxt = Ntf_GetStatusTxtFromStatusBits (Status);
 
          if (Status & Ntf_STATUS_BIT_REMOVED)	// The source of the notification was removed
@@ -1851,7 +1852,7 @@ static void Ntf_SendPendingNotifByEMailToOneUsr (struct UsrData *ToUsrDat,unsign
 		   FileNameMail);
 	 ReturnCode = system (Command);
 	 if (ReturnCode == -1)
-	    Lay_ShowErrorAndExit ("Error when running script to send email.");
+	    Err_ShowErrorAndExit ("Error when running script to send email.");
 
 	 /***** Remove temporary file *****/
 	 unlink (FileNameMail);
@@ -1928,9 +1929,9 @@ static void Ntf_GetNumNotifSent (long DegCod,long CrsCod,
      {
       row = mysql_fetch_row (mysql_res);
       if (sscanf (row[0],"%u",NumEvents) != 1)
-         Lay_ShowErrorAndExit ("Error when getting number of notifications sent by email.");
+         Err_ShowErrorAndExit ("Error when getting number of notifications sent by email.");
       if (sscanf (row[1],"%u",NumMails) != 1)
-         Lay_ShowErrorAndExit ("Error when getting number of notifications sent by email.");
+         Err_ShowErrorAndExit ("Error when getting number of notifications sent by email.");
      }
    else
       *NumEvents = *NumMails = 0;
diff --git a/swad_pagination.c b/swad_pagination.c
index 4869d1dc..55513ca5 100644
--- a/swad_pagination.c
+++ b/swad_pagination.c
@@ -34,6 +34,7 @@
 #include "swad_agenda.h"
 #include "swad_attendance.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_exam.h"
 #include "swad_form.h"
 #include "swad_forum.h"
@@ -269,9 +270,9 @@ void Pag_WriteLinksToPages (Pag_WhatPaginate_t WhatPaginate,
                break;
            }
 	 if (asprintf (&ClassLink,"BT_LINK LT %s",ClassTxt) < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
          if (asprintf (&Title,Txt_Page_X_of_Y,1,Pagination->NumPags) < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
          HTM_BUTTON_SUBMIT_Begin (Title,ClassLink,NULL);
          free (Title);
          free (ClassLink);
@@ -296,7 +297,7 @@ void Pag_WriteLinksToPages (Pag_WhatPaginate_t WhatPaginate,
    if (Pagination->MoreThanOnePage)
      {
       if (asprintf (&ClassLink,"BT_LINK PAG %s",ClassTxt) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
 
       /***** Possible link to page 1 *****/
       if (Pagination->StartPage > 1)
@@ -396,7 +397,7 @@ void Pag_WriteLinksToPages (Pag_WhatPaginate_t WhatPaginate,
                break;
            }
          if (asprintf (&Title,Txt_Page_X_of_Y,1,Pagination->NumPags) < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
          HTM_BUTTON_SUBMIT_Begin (Title,ClassLink,NULL);
          HTM_Unsigned (1);
          HTM_BUTTON_End ();
@@ -510,7 +511,7 @@ void Pag_WriteLinksToPages (Pag_WhatPaginate_t WhatPaginate,
            }
          if (asprintf (&Title,Txt_Page_X_of_Y,
 		       Pagination->LeftPage,Pagination->NumPags) < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
          HTM_BUTTON_SUBMIT_Begin (Title,ClassLink,NULL);
          HTM_Unsigned (Pagination->LeftPage);
          HTM_BUTTON_End ();
@@ -530,7 +531,7 @@ void Pag_WriteLinksToPages (Pag_WhatPaginate_t WhatPaginate,
 	   NumPage++)
         {
          if (asprintf (&Title,Txt_Page_X_of_Y,NumPage,Pagination->NumPags) < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
          if (!LinkToPagCurrent && NumPage == Pagination->CurrentPage)
            {
             HTM_SPAN_Begin ("title=\"%s\" class=\"PAG_CUR %s\"",Title,ClassTxt);
@@ -747,7 +748,7 @@ void Pag_WriteLinksToPages (Pag_WhatPaginate_t WhatPaginate,
            }
          if (asprintf (&Title,Txt_Page_X_of_Y,
 		       Pagination->RightPage,Pagination->NumPags) < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
          HTM_BUTTON_SUBMIT_Begin (Title,ClassLink,NULL);
          HTM_Unsigned (Pagination->RightPage);
          HTM_BUTTON_End ();
@@ -860,7 +861,7 @@ void Pag_WriteLinksToPages (Pag_WhatPaginate_t WhatPaginate,
            }
          if (asprintf (&Title,Txt_Page_X_of_Y,
 		       Pagination->NumPags,Pagination->NumPags) < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
          HTM_BUTTON_SUBMIT_Begin (Title,ClassLink,NULL);
          HTM_Unsigned (Pagination->NumPags);
          HTM_BUTTON_End ();
diff --git a/swad_parameter.c b/swad_parameter.c
index 69623089..189ec65f 100644
--- a/swad_parameter.c
+++ b/swad_parameter.c
@@ -32,6 +32,7 @@
 
 #include "swad_action.h"
 #include "swad_config.h"
+#include "swad_error.h"
 #include "swad_global.h"
 #include "swad_HTML.h"
 #include "swad_parameter.h"
@@ -179,7 +180,7 @@ static void Par_GetBoundary (void)
 
    /***** Check that boundary string is not too long *****/
    if (2 + 2 + strlen (PtrToBoundary) > Par_MAX_BYTES_BOUNDARY_WITH_CR_LF)
-      Lay_ShowErrorAndExit ("Delimiter string too long.");
+      Err_ShowErrorAndExit ("Delimiter string too long.");
 
    /***** Create boundary strings *****/
    snprintf (Gbl.Boundary.StrWithoutCRLF,sizeof (Gbl.Boundary.StrWithoutCRLF),
@@ -258,7 +259,7 @@ static void Par_CreateListOfParamsFromQueryString (void)
      {
       /* Allocate space for a new parameter initialized to 0 */
       if ((NewParam = calloc (1,sizeof (*NewParam))) == NULL)
-          Lay_NotEnoughMemoryExit ();
+          Err_NotEnoughMemoryExit ();
 
       /* Link the previous element in list with the current element */
       if (CurPos == 0)
@@ -334,7 +335,7 @@ static void Par_CreateListOfParamsFromTmpFile (void)
 	   {
 	    /* Allocate space for a new parameter initialized to 0 */
 	    if ((NewParam = calloc (1,sizeof (*NewParam))) == NULL)
-               Lay_NotEnoughMemoryExit ();
+               Err_NotEnoughMemoryExit ();
 
 	    /* Link the previous element in list with the current element */
 	    if (CurPos == 0)
@@ -565,7 +566,7 @@ unsigned Par_GetParameter (tParamType ParamType,const char *ParamName,
 	                       "Multiple parameter <strong>%s</strong> too large,"
 			       " it exceed the maximum allowed size (%lu bytes).",
 			       ParamName,(unsigned long) MaxBytes);
-		     Lay_ShowErrorAndExit (ErrorTxt);
+		     Err_ShowErrorAndExit (ErrorTxt);
 		    }
 
 		  /* Copy separator */
@@ -584,7 +585,7 @@ unsigned Par_GetParameter (tParamType ParamType,const char *ParamName,
 	                       "Parameter <strong>%s</strong> too large,"
 			       " it exceed the maximum allowed size (%lu bytes).",
 			       ParamName,(unsigned long) MaxBytes);
-		     Lay_ShowErrorAndExit (ErrorTxt);
+		     Err_ShowErrorAndExit (ErrorTxt);
 		    }
 
 		  /* Copy parameter value */
@@ -602,7 +603,7 @@ unsigned Par_GetParameter (tParamType ParamType,const char *ParamName,
 			   fseek (Gbl.F.Tmp,Param->Value.Start,SEEK_SET);
 			   if (fread (PtrDst,sizeof (char),Param->Value.Length,Gbl.F.Tmp) !=
 			       Param->Value.Length)
-			      Lay_ShowErrorAndExit ("Error while getting value of parameter.");
+			      Err_ShowErrorAndExit ("Error while getting value of parameter.");
 		          }
 			break;
 		    }
diff --git a/swad_password.c b/swad_password.c
index 93a54853..ab4b873f 100644
--- a/swad_password.c
+++ b/swad_password.c
@@ -35,6 +35,7 @@
 #include "swad_box.h"
 #include "swad_database.h"
 #include "swad_enrolment.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_HTML.h"
@@ -382,14 +383,14 @@ void Pwd_ChkIdLoginAndSendNewPwd (void)
 	       Pwd_SetMyPendingPassword (NewRandomPlainPassword);
 	       break;
 	    case 1:
-	       Lay_ShowErrorAndExit (Txt_There_was_a_problem_sending_an_email_automatically);
+	       Err_ShowErrorAndExit (Txt_There_was_a_problem_sending_an_email_automatically);
 	       break;
 	    default:
 	       snprintf (ErrorTxt,sizeof (ErrorTxt),
 			 "Internal error: an email message has not been sent successfully."
 			 " Error code returned by the script: %d",
 			 ReturnCode);
-	       Lay_ShowErrorAndExit (ErrorTxt);
+	       Err_ShowErrorAndExit (ErrorTxt);
 	       break;
 	   }
      }
@@ -457,7 +458,7 @@ int Pwd_SendNewPasswordByEmail (char NewRandomPlainPassword[Pwd_MAX_BYTES_PLAIN_
 	     FileNameMail);
    ReturnCode = system (Command);
    if (ReturnCode == -1)
-      Lay_ShowErrorAndExit ("Error when running script to send email.");
+      Err_ShowErrorAndExit ("Error when running script to send email.");
 
    /***** Remove temporary file *****/
    unlink (FileNameMail);
@@ -578,7 +579,7 @@ static unsigned Pwd_GetNumOtherUsrsWhoUseThisPassword (const char *EncryptedPass
    if (UsrCod > 0)
      {
       if (asprintf (&SubQuery," AND UsrCod<>%ld",UsrCod) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
      }
    else
       SubQuery = "";
diff --git a/swad_photo.c b/swad_photo.c
index 24f749d9..ef768de2 100644
--- a/swad_photo.c
+++ b/swad_photo.c
@@ -40,6 +40,7 @@
 #include "swad_config.h"
 #include "swad_database.h"
 #include "swad_enrolment.h"
+#include "swad_error.h"
 #include "swad_file.h"
 #include "swad_file_browser.h"
 #include "swad_follow.h"
@@ -671,7 +672,7 @@ static bool Pho_ReceivePhotoAndDetectFaces (bool ItsMe,const struct UsrData *Usr
 	     FileNamePhotoTmp);
    ReturnCode = system (Command);
    if (ReturnCode == -1)
-      Lay_ShowErrorAndExit ("Error when running command to process photo and detect faces.");
+      Err_ShowErrorAndExit ("Error when running command to process photo and detect faces.");
 
    /***** Write message depending on return code *****/
    ReturnCode = WEXITSTATUS(ReturnCode);
@@ -682,7 +683,7 @@ static bool Pho_ReceivePhotoAndDetectFaces (bool ItsMe,const struct UsrData *Usr
          snprintf (FileNameTxtMap,sizeof (FileNameTxtMap),"%s/%s_map.txt",
                    Cfg_PATH_PHOTO_TMP_PUBLIC,Gbl.UniqueNameEncrypted);
          if ((FileTxtMap = fopen (FileNameTxtMap,"rb")) == NULL)
-            Lay_ShowErrorAndExit ("Can not read text file with coordinates of detected faces.");
+            Err_ShowErrorAndExit ("Can not read text file with coordinates of detected faces.");
 
          /***** Read file with coordinates for image map and compute the number of faces *****/
          NumLastForm = Gbl.Form.Num;
@@ -730,7 +731,7 @@ static bool Pho_ReceivePhotoAndDetectFaces (bool ItsMe,const struct UsrData *Usr
 	           "Photo could not be processed successfully.<br />"
                    "Error code returned by the program of processing: %d",
                    ReturnCode);
-         Lay_ShowErrorAndExit (ErrorTxt);
+         Err_ShowErrorAndExit (ErrorTxt);
          break;
      }
 
@@ -906,7 +907,7 @@ static void Pho_UpdatePhoto2 (void)
      {
       HTM_TD_Begin ("class=\"DAT CT\" style=\"width:33%%;\"");
       if (asprintf (&Img,"%s_paso%u.jpg",Gbl.Usrs.FileNamePhoto,NumPhoto + 1) < 0)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
       HTM_IMG (Cfg_URL_PHOTO_TMP_PUBLIC,Img,Txt_PHOTO_PROCESSING_CAPTIONS[NumPhoto],
 	       "style=\"width:%upx;height:%upx;\"",
 	       Pho_PHOTO_REAL_WIDTH,Pho_PHOTO_REAL_HEIGHT);
@@ -1048,7 +1049,7 @@ bool Pho_BuildLinkToPhoto (const struct UsrData *UsrDat,char PhotoURL[PATH_MAX +
       /***** Create a symbolic link to the private photo, if not exists *****/
       if (!Fil_CheckIfPathExists (PathPublPhoto))
          if (symlink (PathPrivPhoto,PathPublPhoto) != 0)
-            Lay_ShowErrorAndExit ("Can not create public link"
+            Err_ShowErrorAndExit ("Can not create public link"
                                  " to access to user's private photo");
 
       /***** Create the public URL of the photo *****/
@@ -1387,7 +1388,7 @@ void Pho_CalcPhotoDegree (void)
    /***** Prevent the computing of an average photo too recently updated *****/
    if (Pho_GetTimeAvgPhotoWasComputed (DegCod) >=
        Gbl.StartExecutionTimeUTC - Cfg_MIN_TIME_TO_RECOMPUTE_AVG_PHOTO)
-      Lay_ShowErrorAndExit ("Average photo has been computed recently.");
+      Err_ShowErrorAndExit ("Average photo has been computed recently.");
 
    /***** Get list of students in this degree *****/
    Usr_GetUnorderedStdsCodesInDeg (DegCod);
@@ -1590,7 +1591,7 @@ static void Pho_ComputeAveragePhoto (long DegCod,Usr_Sex_t Sex,Rol_Role_t Role,
    /***** Build name for file with average photo *****/
    if (asprintf (&PathRelAvgPhoto,"%s/%ld_%s.jpg",
                  DirAvgPhotosRelPath,DegCod,Usr_StringsSexDB[Sex]) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Remove old file if exists *****/
    if (Fil_CheckIfPathExists (PathRelAvgPhoto))  // If file exists
@@ -1599,9 +1600,9 @@ static void Pho_ComputeAveragePhoto (long DegCod,Usr_Sex_t Sex,Rol_Role_t Role,
    /***** Build names for text file with photo paths *****/
    if (asprintf (&FileNamePhotoNames,"%s/%ld.txt",
 	         Cfg_PATH_PHOTO_TMP_PRIVATE,DegCod) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    if ((FilePhotoNames = fopen (FileNamePhotoNames,"wb")) == NULL)
-      Lay_ShowErrorAndExit ("Can not open file to compute average photo.");
+      Err_ShowErrorAndExit ("Can not open file to compute average photo.");
 
    /***** Loop writing file names in text file *****/
    for (NumUsr = 0;
@@ -1632,11 +1633,11 @@ static void Pho_ComputeAveragePhoto (long DegCod,Usr_Sex_t Sex,Rol_Role_t Role,
 	        FileNamePhotoNames,PathRelAvgPhoto);
       ReturnCode = system (StrCallToProgram);
       if (ReturnCode == -1)
-	 Lay_ShowErrorAndExit ("Error when running program that computes the average photo.");
+	 Err_ShowErrorAndExit ("Error when running program that computes the average photo.");
 
       /* Write message depending on the return code */
       if (WEXITSTATUS(ReturnCode))
-	 Lay_ShowErrorAndExit ("The average photo has not been computed successfully.");
+	 Err_ShowErrorAndExit ("The average photo has not been computed successfully.");
      }
 
    free (PathRelAvgPhoto);
@@ -2135,7 +2136,7 @@ static void Pho_ShowOrPrintClassPhotoDegrees (struct Pho_DegPhotos *DegPhotos,
 	{
 	 /***** Get next degree *****/
 	 if ((Deg.DegCod = DB_GetNextCode (mysql_res)) < 0)
-	    Lay_WrongDegreeExit ();
+	    Err_WrongDegreeExit ();
 
 	 /* Get data of degree */
 	 Deg_GetDataOfDegreeByCod (&Deg);
@@ -2232,7 +2233,7 @@ static void Pho_ShowOrPrintListDegrees (struct Pho_DegPhotos *DegPhotos,
 
 	 /* Get degree code (row[0]) */
 	 if ((Deg.DegCod = Str_ConvertStrCodToLongCod (row[0])) < 0)
-	    Lay_WrongDegreeExit ();
+	    Err_WrongDegreeExit ();
 
 	 /* Get data of degree */
 	 Deg_GetDataOfDegreeByCod (&Deg);
diff --git a/swad_place.c b/swad_place.c
index c722b4ea..07e7da4a 100644
--- a/swad_place.c
+++ b/swad_place.c
@@ -32,6 +32,7 @@
 #include "swad_box.h"
 #include "swad_constant.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_HTML.h"
@@ -399,7 +400,7 @@ void Plc_GetListPlaces (struct Plc_Places *Places)
       /***** Create list with courses in center *****/
       if ((Places->Lst = calloc ((size_t) Places->Num,
                                  sizeof (*Places->Lst))) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
 
       /***** Get the places *****/
       for (NumPlc = 0;
@@ -413,7 +414,7 @@ void Plc_GetListPlaces (struct Plc_Places *Places)
 
          /* Get place code (row[0]) */
          if ((Plc->PlcCod = Str_ConvertStrCodToLongCod (row[0])) <= 0)
-            Lay_WrongPlaceExit ();
+            Err_WrongPlaceExit ();
 
          /* Get the short (row[1]) and full (row[2]) names of the place */
          Str_Copy (Plc->ShrtName,row[1],sizeof (Plc->ShrtName) - 1);
@@ -616,7 +617,7 @@ void Plc_RemovePlace (void)
 
    /***** Get place code *****/
    if ((Plc_EditingPlc->PlcCod = Plc_GetParamPlcCod ()) <= 0)
-      Lay_WrongPlaceExit ();
+      Err_WrongPlaceExit ();
 
    /***** Get data of the place from database *****/
    Plc_GetDataOfPlaceByCod (Plc_EditingPlc);
@@ -700,7 +701,7 @@ static void Plc_RenamePlace (Cns_ShrtOrFullName_t ShrtOrFullName)
    /***** Get parameters from form *****/
    /* Get the code of the place */
    if ((Plc_EditingPlc->PlcCod = Plc_GetParamPlcCod ()) <= 0)
-      Lay_WrongPlaceExit ();
+      Err_WrongPlaceExit ();
 
    /* Get the new name for the place */
    Par_GetParToText (ParamName,NewPlcName,MaxBytes);
@@ -941,11 +942,11 @@ static void Plc_EditingPlaceConstructor (void)
   {
    /***** Pointer must be NULL *****/
    if (Plc_EditingPlc != NULL)
-      Lay_WrongPlaceExit ();
+      Err_WrongPlaceExit ();
 
    /***** Allocate memory for place *****/
    if ((Plc_EditingPlc = malloc (sizeof (*Plc_EditingPlc))) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Reset place *****/
    Plc_EditingPlc->PlcCod      = -1L;
diff --git a/swad_plugin.c b/swad_plugin.c
index b81476cc..2f7fae7c 100644
--- a/swad_plugin.c
+++ b/swad_plugin.c
@@ -39,6 +39,7 @@ TODO: Check if web service is called from an authorized IP.
 #include "swad_constant.h"
 #include "swad_cryptography.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_HTML.h"
@@ -247,7 +248,7 @@ static void Plg_GetListPlugins (void)
       /***** Create list with plugins *****/
       if ((Gbl.Plugins.Lst = calloc ((size_t) Gbl.Plugins.Num,
                                      sizeof (*Gbl.Plugins.Lst))) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
 
       /***** Get the plugins *****/
       for (NumPlg = 0;
@@ -261,7 +262,7 @@ static void Plg_GetListPlugins (void)
 
          /* Get plugin code (row[0]) */
          if ((Plg->PlgCod = Str_ConvertStrCodToLongCod (row[0])) <= 0)
-            Lay_WrongPluginExit ();
+            Err_WrongPluginExit ();
 
          /* Get name (row[1]), description (row[2), logo (row[3]),
           * application key (row[4]), URL (row[5]) and IP (row[6]) of the plugin */
@@ -493,7 +494,7 @@ void Plg_RemovePlugin (void)
 
    /***** Get plugin code *****/
    if ((Plg_EditingPlg->PlgCod = Plg_GetParamPlgCod ()) <= 0)
-      Lay_WrongPluginExit ();
+      Err_WrongPluginExit ();
 
    /***** Get data of the plugin from database *****/
    Plg_GetDataOfPluginByCod (Plg_EditingPlg);
@@ -527,7 +528,7 @@ void Plg_RenamePlugin (void)
    /***** Get parameters from form *****/
    /* Get the code of the plugin */
    if ((Plg_EditingPlg->PlgCod = Plg_GetParamPlgCod ()) <= 0)
-      Lay_WrongPluginExit ();
+      Err_WrongPluginExit ();
 
    /* Get the new name for the plugin */
    Par_GetParToText ("Name",NewPlgName,Plg_MAX_BYTES_PLUGIN_NAME);
@@ -606,7 +607,7 @@ void Plg_ChangePlgDescription (void)
    /***** Get parameters from form *****/
    /* Get the code of the plugin */
    if ((Plg_EditingPlg->PlgCod = Plg_GetParamPlgCod ()) <= 0)
-      Lay_WrongPluginExit ();
+      Err_WrongPluginExit ();
 
    /* Get the new description for the plugin */
    Par_GetParToText ("Description",NewDescription,Plg_MAX_BYTES_PLUGIN_DESCRIPTION);
@@ -653,7 +654,7 @@ void Plg_ChangePlgLogo (void)
    /***** Get parameters from form *****/
    /* Get the code of the plugin */
    if ((Plg_EditingPlg->PlgCod = Plg_GetParamPlgCod ()) <= 0)
-      Lay_WrongPluginExit ();
+      Err_WrongPluginExit ();
 
    /* Get the new logo for the plugin */
    Par_GetParToText ("Logo",NewLogo,Plg_MAX_BYTES_PLUGIN_LOGO);
@@ -699,7 +700,7 @@ void Plg_ChangePlgAppKey (void)
    /***** Get parameters from form *****/
    /* Get the code of the plugin */
    if ((Plg_EditingPlg->PlgCod = Plg_GetParamPlgCod ()) <= 0)
-      Lay_WrongPluginExit ();
+      Err_WrongPluginExit ();
 
    /* Get the new logo for the plugin */
    Par_GetParToText ("AppKey",NewAppKey,Plg_MAX_BYTES_PLUGIN_APP_KEY);
@@ -745,7 +746,7 @@ void Plg_ChangePlgURL (void)
    /***** Get parameters from form *****/
    /* Get the code of the plugin */
    if ((Plg_EditingPlg->PlgCod = Plg_GetParamPlgCod ()) <= 0)
-      Lay_WrongPluginExit ();
+      Err_WrongPluginExit ();
 
    /* Get the new URL for the plugin */
    Par_GetParToText ("URL",NewURL,Cns_MAX_BYTES_WWW);
@@ -791,7 +792,7 @@ void Plg_ChangePlgIP (void)
    /***** Get parameters from form *****/
    /* Get the code of the plugin */
    if ((Plg_EditingPlg->PlgCod = Plg_GetParamPlgCod ()) <= 0)
-      Lay_WrongPluginExit ();
+      Err_WrongPluginExit ();
 
    /* Get the new IP for the plugin */
    Par_GetParToText ("IP",NewIP,Cns_MAX_BYTES_IP);
@@ -1047,11 +1048,11 @@ static void Plg_EditingPluginConstructor (void)
   {
    /***** Pointer must be NULL *****/
    if (Plg_EditingPlg != NULL)
-      Lay_WrongPluginExit ();
+      Err_WrongPluginExit ();
 
    /***** Allocate memory for plugin *****/
    if ((Plg_EditingPlg = malloc (sizeof (*Plg_EditingPlg))) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Reset plugin *****/
    Plg_EditingPlg->PlgCod         = -1L;
diff --git a/swad_profile.c b/swad_profile.c
index 8d65287e..522a7507 100644
--- a/swad_profile.c
+++ b/swad_profile.c
@@ -33,6 +33,7 @@
 #include "swad_box.h"
 #include "swad_config.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_figure.h"
 #include "swad_follow.h"
 #include "swad_form.h"
@@ -976,7 +977,7 @@ static void Prf_ShowRanking (unsigned Rank,unsigned NumUsrs)
    Par_PutHiddenParamUnsigned (NULL,"FigureType",(unsigned) Fig_USERS_RANKING);
    if (asprintf (&Title,"#%u %s %u",
                  Rank,Txt_of_PART_OF_A_TOTAL,NumUsrs) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    HTM_BUTTON_SUBMIT_Begin (Title,The_ClassFormLinkOutBox[Gbl.Prefs.Theme],NULL);
    free (Title);
    HTM_TxtF ("#%u",Rank);
@@ -1605,7 +1606,7 @@ static void Prf_GetAndShowRankingFigure (const char *FieldName)
 			 FieldName,FieldName);
          break;
       default:
-         Lay_WrongScopeExit ();
+         Err_WrongScopeExit ();
          break;
      }
 
@@ -1645,7 +1646,7 @@ void Prf_ShowRankingFigure (MYSQL_RES **mysql_res,unsigned NumUsrs)
 
 	 /* Get figure (row[1]) */
 	 if (sscanf (row[1],"%ld",&Figure) != 1)
-	    Lay_ShowErrorAndExit ("Error reading user's figure.");
+	    Err_ShowErrorAndExit ("Error reading user's figure.");
 
 	 if (Figure < FigureHigh)
 	   {
@@ -1834,7 +1835,7 @@ void Prf_GetAndShowRankingClicksPerDay (void)
 			 Gbl.Hierarchy.Crs.CrsCod);
          break;
       default:
-         Lay_WrongScopeExit ();
+         Err_WrongScopeExit ();
          break;
      }
 
diff --git a/swad_program.c b/swad_program.c
index e6296e42..958f1447 100644
--- a/swad_program.c
+++ b/swad_program.c
@@ -34,6 +34,7 @@
 
 #include "swad_box.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_figure.h"
 #include "swad_form.h"
 #include "swad_global.h"
@@ -495,7 +496,7 @@ static void Prg_WriteRowItem (unsigned NumItem,struct ProgramItem *Item,
 	StartEndTime++)
      {
       if (asprintf (&Id,"scd_date_%u_%u",(unsigned) StartEndTime,UniqueId) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       if (PrintView)
 	 HTM_TD_Begin ("id=\"%s\" class=\"PRG_DATE %s LT\"",
 		       Id,
@@ -602,7 +603,7 @@ static void Prg_SetTitleClass (char **TitleClass,unsigned Level,bool LightStyle)
 			     5,
 		 LightStyle ? "PRG_HIDDEN" :
 			      "") < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
   }
 
 static void Prg_FreeTitleClass (char *TitleClass)
@@ -668,7 +669,7 @@ static void Prg_CreateLevels (void)
       */
       if ((Prg_Gbl.Levels = calloc (1 + MaxLevel + 1,
                                     sizeof (*Prg_Gbl.Levels))) == NULL)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
      }
    else
       Prg_Gbl.Levels = NULL;
@@ -993,7 +994,7 @@ static void Prg_GetListItems (void)
       /***** Create list of program items *****/
       if ((Prg_Gbl.List.Items = calloc (Prg_Gbl.List.NumItems,
 				        sizeof (*Prg_Gbl.List.Items))) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
 
       /***** Get the program items codes *****/
       for (NumItem = 0;
@@ -1005,7 +1006,7 @@ static void Prg_GetListItems (void)
 
          /* Get code of the program item (row[0]) */
          if ((Prg_Gbl.List.Items[NumItem].ItmCod = Str_ConvertStrCodToLongCod (row[0])) <= 0)
-            Lay_WrongItemExit ();
+            Err_WrongItemExit ();
 
          /* Get index of the program item (row[1]) */
          Prg_Gbl.List.Items[NumItem].Index = Str_ConvertStrToUnsigned (row[1]);
@@ -1201,7 +1202,7 @@ static unsigned Prg_GetNumItemFromItmCod (long ItmCod)
 
    /***** List of items must be filled *****/
    if (!Prg_Gbl.List.IsRead || Prg_Gbl.List.Items == NULL)
-      Lay_WrongItemsListExit ();
+      Err_WrongItemsListExit ();
 
    /***** Find item code in list *****/
    for (NumItem = 0;
@@ -1211,7 +1212,7 @@ static unsigned Prg_GetNumItemFromItmCod (long ItmCod)
 	 return NumItem;
 
    /***** Not found *****/
-   Lay_WrongItemExit ();
+   Err_WrongItemExit ();
    return 0;	// Not reached
   }
 
@@ -1233,7 +1234,7 @@ void Prg_ReqRemItem (void)
    Item.Hierarchy.ItmCod = Prg_GetParamItmCod ();
    Prg_GetDataOfItemByCod (&Item);
    if (Item.Hierarchy.ItmCod <= 0)
-      Lay_WrongItemExit ();
+      Err_WrongItemExit ();
 
    /***** Show question and button to remove the program item *****/
    Ale_ShowAlertAndButton (ActRemPrgItm,NULL,NULL,
@@ -1269,7 +1270,7 @@ void Prg_RemoveItem (void)
    Item.Hierarchy.ItmCod = Prg_GetParamItmCod ();
    Prg_GetDataOfItemByCod (&Item);
    if (Item.Hierarchy.ItmCod <= 0)
-      Lay_WrongItemExit ();
+      Err_WrongItemExit ();
 
    /***** Indexes of items *****/
    Prg_SetItemRangeWithAllChildren (Prg_GetNumItemFromItmCod (Item.Hierarchy.ItmCod),
@@ -1326,7 +1327,7 @@ static void Prg_HideUnhideItem (char YN)
    Item.Hierarchy.ItmCod = Prg_GetParamItmCod ();
    Prg_GetDataOfItemByCod (&Item);
    if (Item.Hierarchy.ItmCod <= 0)
-      Lay_WrongItemExit ();
+      Err_WrongItemExit ();
 
    /***** Hide/unhide program item *****/
    DB_QueryUPDATE ("can not change program item",
@@ -1381,7 +1382,7 @@ static void Prg_MoveUpDownItem (Prg_MoveUpDown_t UpDown)
    Item.Hierarchy.ItmCod = Prg_GetParamItmCod ();
    Prg_GetDataOfItemByCod (&Item);
    if (Item.Hierarchy.ItmCod <= 0)
-      Lay_WrongItemExit ();
+      Err_WrongItemExit ();
 
    /***** Move up/down item *****/
    NumItem = Prg_GetNumItemFromItmCod (Item.Hierarchy.ItmCod);
@@ -1615,7 +1616,7 @@ static void Prg_MoveLeftRightItem (Prg_MoveLeftRight_t LeftRight)
    Item.Hierarchy.ItmCod = Prg_GetParamItmCod ();
    Prg_GetDataOfItemByCod (&Item);
    if (Item.Hierarchy.ItmCod <= 0)
-      Lay_WrongItemExit ();
+      Err_WrongItemExit ();
 
    /***** Move up/down item *****/
    NumItem = Prg_GetNumItemFromItmCod (Item.Hierarchy.ItmCod);
@@ -1663,7 +1664,7 @@ static void Prg_SetItemRangeEmpty (struct ItemRange *ItemRange)
   {
    /***** List of items must be filled *****/
    if (!Prg_Gbl.List.IsRead)
-      Lay_WrongItemsListExit ();
+      Err_WrongItemsListExit ();
 
    /***** Range is empty *****/
    if (Prg_Gbl.List.NumItems)
@@ -1678,7 +1679,7 @@ static void Prg_SetItemRangeOnlyItem (unsigned Index,struct ItemRange *ItemRange
   {
    /***** List of items must be filled *****/
    if (!Prg_Gbl.List.IsRead)
-      Lay_WrongItemsListExit ();
+      Err_WrongItemsListExit ();
 
    /***** Range includes only this item *****/
    ItemRange->Begin =
@@ -1689,11 +1690,11 @@ static void Prg_SetItemRangeWithAllChildren (unsigned NumItem,struct ItemRange *
   {
    /***** List of items must be filled *****/
    if (!Prg_Gbl.List.IsRead)
-      Lay_WrongItemsListExit ();
+      Err_WrongItemsListExit ();
 
    /***** Number of item must be in the correct range *****/
    if (NumItem >= Prg_Gbl.List.NumItems)
-      Lay_WrongItemExit ();
+      Err_WrongItemExit ();
 
    /***** Range includes this item and all its children *****/
    ItemRange->Begin = Prg_Gbl.List.Items[NumItem                   ].Index;
@@ -1712,7 +1713,7 @@ static unsigned Prg_GetLastChild (int NumItem)
    /***** Trivial check: if item is wrong, there are no children *****/
    if (NumItem < 0 ||
        NumItem >= (int) Prg_Gbl.List.NumItems)
-      Lay_WrongItemExit ();
+      Err_WrongItemExit ();
 
    /***** Get next brother after item *****/
    // 0 <= NumItem < Prg_Gbl.List.NumItems
@@ -2013,7 +2014,7 @@ void Prg_ReceiveFormChgItem (void)
    NewItem.Hierarchy.ItmCod = Prg_GetParamItmCod ();
    Prg_GetDataOfItemByCod (&NewItem);
    if (NewItem.Hierarchy.ItmCod <= 0)
-      Lay_WrongItemExit ();
+      Err_WrongItemExit ();
 
    /***** Get data of the old (current) program item from database *****/
    OldItem.Hierarchy.ItmCod = NewItem.Hierarchy.ItmCod;
diff --git a/swad_project.c b/swad_project.c
index e8a7ce02..57d54b1b 100644
--- a/swad_project.c
+++ b/swad_project.c
@@ -35,6 +35,7 @@
 #include "swad_box.h"
 #include "swad_database.h"
 #include "swad_department.h"
+#include "swad_error.h"
 #include "swad_figure.h"
 #include "swad_form.h"
 #include "swad_global.h"
@@ -383,7 +384,7 @@ static void Prj_ShowProjects (struct Prj_Projects *Projects)
          Prj_GetSelectedUsrsAndShowTheirPrjs (Projects);
          break;
       default:
-	 Lay_WrongWhoExit ();
+	 Err_WrongWhoExit ();
 	 break;
      }
   }
@@ -876,7 +877,7 @@ static Prj_HiddenVisibl_t Prj_GetHiddenParamHidVis (void)
 					  (unsigned) Prj_FILTER_HIDDEN_DEFAULT |
 					  (unsigned) Prj_FILTER_VISIBL_DEFAULT);
       default:
-	 Lay_WrongRoleExit ();
+	 Err_WrongRoleExit ();
          return Prj_NEW_PRJ_HIDDEN_VISIBL_DEFAULT;	// Not reached
      }
   }
@@ -1303,7 +1304,7 @@ static void Prj_ShowOneProject (struct Prj_Projects *Projects,
    /* Creation date/time */
    UniqueId++;
    if (asprintf (&Id,"prj_creat_%u",UniqueId) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    switch (ProjectView)
      {
       case Prj_LIST_PROJECTS:
@@ -1324,7 +1325,7 @@ static void Prj_ShowOneProject (struct Prj_Projects *Projects,
    /* Modification date/time */
    UniqueId++;
    if (asprintf (&Id,"prj_modif_%u",UniqueId) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    switch (ProjectView)
      {
       case Prj_LIST_PROJECTS:
@@ -1691,7 +1692,7 @@ static void Prj_ShowTableAllProjectsOneRow (struct Prj_Project *Prj)
    /***** Start date/time *****/
    UniqueId++;
    if (asprintf (&Id,"prj_creat_%u",UniqueId) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    HTM_TD_Begin ("id=\"%s\" class=\"LT %s COLOR%u\"",
 		 Id,ClassDate,Gbl.RowEvenOdd);
    Dat_WriteLocalDateHMSFromUTC (Id,Prj->CreatTime,
@@ -1703,7 +1704,7 @@ static void Prj_ShowTableAllProjectsOneRow (struct Prj_Project *Prj)
    /***** End date/time *****/
    UniqueId++;
    if (asprintf (&Id,"prj_modif_%u",UniqueId) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    HTM_TD_Begin ("id=\"%s\" class=\"LT %s COLOR%u\"",
 		 Id,ClassDate,Gbl.RowEvenOdd);
    Dat_WriteLocalDateHMSFromUTC (Id,Prj->ModifTime,
@@ -2431,12 +2432,12 @@ static void Prj_FormToSelectUsrs (struct Prj_Projects *Projects,
    /***** Get parameters *****/
    Prj_GetParams (Projects);
    if ((Projects->PrjCod = Prj.PrjCod = Prj_GetParamPrjCod ()) <= 0)
-      Lay_WrongProjectExit ();
+      Err_WrongProjectExit ();
 
    /***** Put form to select users *****/
    if (asprintf (&TxtButton,Txt_Add_USERS,
 	         Txt_PROJECT_ROLES_PLURAL_abc[RoleInProject]) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    Usr_PutFormToSelectUsrsToGoToAct (&Prj_MembersToAdd,
 				     ActionAddUsr[RoleInProject],
 				     Prj_PutCurrentParams,Projects,
@@ -2509,7 +2510,7 @@ static void Prj_AddUsrsToProject (Prj_RoleInProject_t RoleInProject)
    /***** Get parameters *****/
    Prj_GetParams (&Projects);
    if ((Projects.PrjCod = Prj.PrjCod = Prj_GetParamPrjCod ()) <= 0)
-      Lay_WrongProjectExit ();
+      Err_WrongProjectExit ();
 
    /***** Add the selected users to project *****/
    Ptr = Prj_MembersToAdd.List[Rol_UNK];
@@ -2611,7 +2612,7 @@ static void Prj_ReqRemUsrFromPrj (struct Prj_Projects *Projects,
    /***** Get parameters *****/
    Prj_GetParams (Projects);
    if ((Projects->PrjCod = Prj.PrjCod = Prj_GetParamPrjCod ()) < 0)
-      Lay_WrongProjectExit ();
+      Err_WrongProjectExit ();
 
    /***** Get data of the project from database *****/
    Prj_GetDataOfProjectByCod (&Prj);
@@ -2696,7 +2697,7 @@ static void Prj_RemUsrFromPrj (Prj_RoleInProject_t RoleInProject)
    /***** Get parameters *****/
    Prj_GetParams (&Projects);
    if ((Projects.PrjCod = Prj.PrjCod = Prj_GetParamPrjCod ()) < 0)
-      Lay_WrongProjectExit ();
+      Err_WrongProjectExit ();
 
    /***** Get data of the project from database *****/
    Prj_GetDataOfProjectByCod (&Prj);
@@ -2879,15 +2880,15 @@ static void Prj_GetListProjects (struct Prj_Projects *Projects)
 	{
 	 case (1 << Prj_ASSIGNED):	// Assigned projects
 	    if (asprintf (&PreNonSubQuery," AND prj_projects.Assigned='Y'") < 0)
-	       Lay_NotEnoughMemoryExit ();
+	       Err_NotEnoughMemoryExit ();
 	    break;
 	 case (1 << Prj_NONASSIG):	// Non-assigned projects
 	    if (asprintf (&PreNonSubQuery," AND prj_projects.Assigned='N'") < 0)
-	       Lay_NotEnoughMemoryExit ();
+	       Err_NotEnoughMemoryExit ();
 	    break;
 	 default:			// All projects
 	    if (asprintf (&PreNonSubQuery,"%s","") < 0)
-	       Lay_NotEnoughMemoryExit ();
+	       Err_NotEnoughMemoryExit ();
 	    break;
 	}
 
@@ -2896,7 +2897,7 @@ static void Prj_GetListProjects (struct Prj_Projects *Projects)
 	{
 	 case Rol_STD:	// Students can view only visible projects
 	    if (asprintf (&HidVisSubQuery," AND prj_projects.Hidden='N'") < 0)
-	       Lay_NotEnoughMemoryExit ();
+	       Err_NotEnoughMemoryExit ();
 	    break;
 	 case Rol_NET:
 	 case Rol_TCH:
@@ -2905,20 +2906,20 @@ static void Prj_GetListProjects (struct Prj_Projects *Projects)
 	      {
 	       case (1 << Prj_HIDDEN):	// Hidden projects
 		  if (asprintf (&HidVisSubQuery," AND prj_projects.Hidden='Y'") < 0)
-	             Lay_NotEnoughMemoryExit ();
+	             Err_NotEnoughMemoryExit ();
 		  break;
 	       case (1 << Prj_VISIBL):	// Visible projects
 		  if (asprintf (&HidVisSubQuery," AND prj_projects.Hidden='N'") < 0)
-	             Lay_NotEnoughMemoryExit ();
+	             Err_NotEnoughMemoryExit ();
 		  break;
 	       default:			// All projects
 		  if (asprintf (&HidVisSubQuery,"%s","") < 0)
-	             Lay_NotEnoughMemoryExit ();
+	             Err_NotEnoughMemoryExit ();
 		  break;
 	      }
 	    break;
 	 default:
-	    Lay_WrongRoleExit ();
+	    Err_WrongRoleExit ();
 	    break;
 	}
 
@@ -2927,12 +2928,12 @@ static void Prj_GetListProjects (struct Prj_Projects *Projects)
         {
 	 if (asprintf (&DptCodSubQuery," AND prj_projects.DptCod=%ld",
 	               Projects->Filter.DptCod) < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
         }
       else	// Any department
 	{
 	 if (asprintf (&DptCodSubQuery,"%s","") < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 	}
 
       /* Query */
@@ -3101,7 +3102,7 @@ static void Prj_GetListProjects (struct Prj_Projects *Projects)
 	      }
 	    break;
 	 default:
-	    Lay_WrongWhoExit ();
+	    Err_WrongWhoExit ();
 	    break;
         }
 
@@ -3115,7 +3116,7 @@ static void Prj_GetListProjects (struct Prj_Projects *Projects)
 	 /***** Create list of projects *****/
 	 if ((Projects->LstPrjCods = calloc ((size_t) NumPrjsFromDB,
 	                                     sizeof (*Projects->LstPrjCods))) == NULL)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Get the projects codes *****/
 	 for (NumPrj = 0;
@@ -3124,7 +3125,7 @@ static void Prj_GetListProjects (struct Prj_Projects *Projects)
 	   {
 	    /* Get next project code */
 	    if ((PrjCod = DB_GetNextCode (mysql_res)) < 0)
-               Lay_WrongProjectExit ();
+               Err_WrongProjectExit ();
 
 	    /* Filter projects depending on faultiness */
 	    switch (Projects->Filter.Faulti)
@@ -3354,7 +3355,7 @@ void Prj_ReqRemProject (void)
    /***** Get parameters *****/
    Prj_GetParams (&Projects);
    if ((Prj.PrjCod = Prj_GetParamPrjCod ()) < 0)
-      Lay_WrongProjectExit ();
+      Err_WrongProjectExit ();
 
    /***** Get data of the project from database *****/
    Prj_GetDataOfProjectByCod (&Prj);
@@ -3370,7 +3371,7 @@ void Prj_ReqRemProject (void)
 	                      Prj.Title);
      }
    else
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Free memory of the project *****/
    Prj_FreeMemProject (&Prj);
@@ -3399,7 +3400,7 @@ void Prj_RemoveProject (void)
    /***** Get parameters *****/
    Prj_GetParams (&Projects);
    if ((Prj.PrjCod = Prj_GetParamPrjCod ()) < 0)
-      Lay_WrongProjectExit ();
+      Err_WrongProjectExit ();
 
    /***** Get data of the project from database *****/
    Prj_GetDataOfProjectByCod (&Prj);	// Inside this function, the course is checked to be the current one
@@ -3442,7 +3443,7 @@ void Prj_RemoveProject (void)
 	             Prj.Title);
      }
    else
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Free memory of the project *****/
    Prj_FreeMemProject (&Prj);
@@ -3469,7 +3470,7 @@ void Prj_HideProject (void)
    /***** Get parameters *****/
    Prj_GetParams (&Projects);
    if ((Prj.PrjCod = Prj_GetParamPrjCod ()) < 0)
-      Lay_WrongProjectExit ();
+      Err_WrongProjectExit ();
 
    /***** Get data of the project from database *****/
    Prj_GetDataOfProjectByCod (&Prj);
@@ -3484,7 +3485,7 @@ void Prj_HideProject (void)
 	              Prj.PrjCod,
 	              Gbl.Hierarchy.Crs.CrsCod);
    else
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Free memory of the project *****/
    Prj_FreeMemProject (&Prj);
@@ -3511,7 +3512,7 @@ void Prj_UnhideProject (void)
    /***** Get parameters *****/
    Prj_GetParams (&Projects);
    if ((Prj.PrjCod = Prj_GetParamPrjCod ()) < 0)
-      Lay_WrongProjectExit ();
+      Err_WrongProjectExit ();
 
    /***** Get data of the project from database *****/
    Prj_GetDataOfProjectByCod (&Prj);
@@ -3526,7 +3527,7 @@ void Prj_UnhideProject (void)
 	              Prj.PrjCod,
 	              Gbl.Hierarchy.Crs.CrsCod);
    else
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Free memory of the project *****/
    Prj_FreeMemProject (&Prj);
@@ -3566,7 +3567,7 @@ void Prj_RequestEditPrj (void)
    /***** Get parameters *****/
    Prj_GetParams (&Projects);
    if ((Projects.PrjCod = Prj.PrjCod = Prj_GetParamPrjCod ()) <= 0)
-      Lay_WrongProjectExit ();
+      Err_WrongProjectExit ();
 
    /***** Form to edit project *****/
    Prj_RequestCreatOrEditPrj (&Projects,&Prj);
@@ -3844,13 +3845,13 @@ static void Prj_EditOneProjectTxtArea (const char *Id,
 void Prj_AllocMemProject (struct Prj_Project *Prj)
   {
    if ((Prj->Description = malloc (Cns_MAX_BYTES_TEXT + 1)) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    if ((Prj->Knowledge   = malloc (Cns_MAX_BYTES_TEXT + 1)) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    if ((Prj->Materials   = malloc (Cns_MAX_BYTES_TEXT + 1)) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
   }
 
 /*****************************************************************************/
@@ -3985,7 +3986,7 @@ void Prj_ReceiveFormProject (void)
       Prj_RequestCreatOrEditPrj (&Projects,&Prj);
      }
    else
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Free memory of the project *****/
    Prj_FreeMemProject (&Prj);
@@ -4295,7 +4296,7 @@ void Prj_ReqLockSelectedPrjsEdition (void)
       Prj_FreeListProjects (&Projects);
      }
    else
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Show projects again *****/
    Prj_ShowProjects (&Projects);
@@ -4334,7 +4335,7 @@ void Prj_ReqUnloSelectedPrjsEdition (void)
       Prj_FreeListProjects (&Projects);
      }
    else
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Show projects again *****/
    Prj_ShowProjects (&Projects);
@@ -4375,7 +4376,7 @@ void Prj_LockSelectedPrjsEdition (void)
       Prj_FreeListProjects (&Projects);
      }
    else
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Show projects again *****/
    Prj_ShowProjects (&Projects);
@@ -4412,7 +4413,7 @@ void Prj_UnloSelectedPrjsEdition (void)
       Prj_FreeListProjects (&Projects);
      }
    else
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Show projects again *****/
    Prj_ShowProjects (&Projects);
@@ -4446,7 +4447,7 @@ static void Prj_FormLockUnlock (const struct Prj_Project *Prj)
 		 Act_GetActCod (Prj_LockActions[Prj->Locked]),
 		 Gbl.Session.Id,
 		 Prj->PrjCod) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    Frm_BeginFormOnSubmit (ActUnk,OnSubmit);
    Ico_PutIconLink (Prj_LockIcons[Prj->Locked],Txt_LOCKED_UNLOCKED[Prj->Locked]);
    Frm_EndForm ();
@@ -4485,7 +4486,7 @@ void Prj_LockProjectEdition (void)
    /***** Get parameters *****/
    Prj_GetParams (&Projects);
    if ((Prj.PrjCod = Prj_GetParamPrjCod ()) < 0)
-      Lay_WrongProjectExit ();
+      Err_WrongProjectExit ();
 
    /***** Get data of the project from database *****/
    Prj_GetDataOfProjectByCod (&Prj);
@@ -4500,7 +4501,7 @@ void Prj_LockProjectEdition (void)
       Prj_FormLockUnlock (&Prj);
      }
    else
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Free memory of the project *****/
    Prj_FreeMemProject (&Prj);
@@ -4535,7 +4536,7 @@ void Prj_UnloProjectEdition (void)
    /***** Get parameters *****/
    Prj_GetParams (&Projects);
    if ((Prj.PrjCod = Prj_GetParamPrjCod ()) < 0)
-      Lay_WrongProjectExit ();
+      Err_WrongProjectExit ();
 
    /***** Get data of the project from database *****/
    Prj_GetDataOfProjectByCod (&Prj);
@@ -4550,7 +4551,7 @@ void Prj_UnloProjectEdition (void)
       Prj_FormLockUnlock (&Prj);
      }
    else
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Free memory of the project *****/
    Prj_FreeMemProject (&Prj);
diff --git a/swad_record.c b/swad_record.c
index ede67cef..6e6132a4 100644
--- a/swad_record.c
+++ b/swad_record.c
@@ -39,6 +39,7 @@
 #include "swad_database.h"
 #include "swad_department.h"
 #include "swad_enrolment.h"
+#include "swad_error.h"
 #include "swad_follow.h"
 #include "swad_form.h"
 #include "swad_global.h"
@@ -219,7 +220,7 @@ void Rec_GetListRecordFieldsInCurrentCrs (void)
       /***** Create a list of fields *****/
       if ((Gbl.Crs.Records.LstFields.Lst = calloc (Gbl.Crs.Records.LstFields.Num,
                                                    sizeof (*Gbl.Crs.Records.LstFields.Lst))) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
 
       /***** Get the fields *****/
       for (NumRow = 0;
@@ -231,7 +232,7 @@ void Rec_GetListRecordFieldsInCurrentCrs (void)
 
          /* Get the code of field (row[0]) */
          if ((Gbl.Crs.Records.LstFields.Lst[NumRow].FieldCod = Str_ConvertStrCodToLongCod (row[0])) <= 0)
-            Lay_WrongRecordFieldExit ();
+            Err_WrongRecordFieldExit ();
 
          /* Name of the field (row[1]) */
          Str_Copy (Gbl.Crs.Records.LstFields.Lst[NumRow].Name,row[1],
@@ -242,7 +243,7 @@ void Rec_GetListRecordFieldsInCurrentCrs (void)
 
          /* Visible or editable by students? (row[3]) */
          if (sscanf (row[3],"%u",&Vis) != 1)
-	    Lay_WrongRecordFieldExit ();
+	    Err_WrongRecordFieldExit ();
          if (Vis < Rec_NUM_TYPES_VISIBILITY)
             Gbl.Crs.Records.LstFields.Lst[NumRow].Visibility = (Rec_VisibilityRecordFields_t) Vis;
          else
@@ -568,7 +569,7 @@ void Rec_ReqRemField (void)
 
    /***** Get the code of field *****/
    if ((Gbl.Crs.Records.Field.FieldCod = Rec_GetFieldCod ()) <= 0)
-      Lay_WrongRecordFieldExit ();
+      Err_WrongRecordFieldExit ();
 
    /***** Check if exists any record with that field filled *****/
    if ((NumRecords = Rec_CountNumRecordsInCurrCrsWithField (Gbl.Crs.Records.Field.FieldCod)))	// There are records with that field filled
@@ -694,7 +695,7 @@ static void Rec_GetFieldByCod (long FieldCod,char Name[Rec_MAX_BYTES_NAME_FIELD
 		       " WHERE CrsCod=%ld"
 			 " AND FieldCod=%ld",
 		       Gbl.Hierarchy.Crs.CrsCod,FieldCod) != 1)
-      Lay_WrongRecordFieldExit ();
+      Err_WrongRecordFieldExit ();
 
    /***** Get the field *****/
    row = mysql_fetch_row (mysql_res);
@@ -707,7 +708,7 @@ static void Rec_GetFieldByCod (long FieldCod,char Name[Rec_MAX_BYTES_NAME_FIELD
 
    /* Visible or editable by students? (row[2]) */
    if (sscanf (row[2],"%u",&Vis) != 1)
-      Lay_WrongRecordFieldExit ();
+      Err_WrongRecordFieldExit ();
    if (Vis < Rec_NUM_TYPES_VISIBILITY)
       *Visibility = (Rec_VisibilityRecordFields_t) Vis;
    else
@@ -725,7 +726,7 @@ void Rec_RemoveField (void)
   {
    /***** Get the code of the field *****/
    if ((Gbl.Crs.Records.Field.FieldCod = Rec_GetFieldCod ()) <= 0)
-      Lay_WrongRecordFieldExit ();
+      Err_WrongRecordFieldExit ();
 
    /***** Borrarlo from the database *****/
    Rec_RemoveFieldFromDB ();
@@ -745,7 +746,7 @@ void Rec_RenameField (void)
    /***** Get parameters of the form *****/
    /* Get the code of the field */
    if ((Gbl.Crs.Records.Field.FieldCod = Rec_GetFieldCod ()) <= 0)
-      Lay_WrongRecordFieldExit ();
+      Err_WrongRecordFieldExit ();
 
    /* Get the new group name */
    Par_GetParToText ("FieldName",NewFieldName,Rec_MAX_BYTES_NAME_FIELD);
@@ -808,7 +809,7 @@ void Rec_ChangeLinesField (void)
    /***** Get parameters of the form *****/
    /* Get the code of field */
    if ((Gbl.Crs.Records.Field.FieldCod = Rec_GetFieldCod ()) <= 0)
-      Lay_WrongRecordFieldExit ();
+      Err_WrongRecordFieldExit ();
 
    /* Get the new number of lines */
    NewNumLines = (unsigned)
@@ -858,7 +859,7 @@ void Rec_ChangeVisibilityField (void)
    /***** Get parameters of the form *****/
    /* Get the code of field */
    if ((Gbl.Crs.Records.Field.FieldCod = Rec_GetFieldCod ()) <= 0)
-      Lay_WrongRecordFieldExit ();
+      Err_WrongRecordFieldExit ();
 
    /* Get the new visibility of the field */
    NewVisibility = (Rec_VisibilityRecordFields_t)
@@ -1691,7 +1692,7 @@ static void Rec_ShowCrsRecord (Rec_CourseRecordViewType_t TypeOfView,
 	       case Rec_CRS_PRINT_SEVERAL_RECORDS:
 		  break;
 	       default:
-		  Lay_NoPermissionExit ();
+		  Err_NoPermissionExit ();
 		  break;
 	      }
 
@@ -1708,7 +1709,7 @@ static void Rec_ShowCrsRecord (Rec_CourseRecordViewType_t TypeOfView,
 		    }
 	   }
 	 else	// Not me ==> I am a student trying to do something forbidden
-	    Lay_NoPermissionExit ();
+	    Err_NoPermissionExit ();
 	 break;
       case Rol_NET:
 	 break;
@@ -1727,7 +1728,7 @@ static void Rec_ShowCrsRecord (Rec_CourseRecordViewType_t TypeOfView,
 	   }
 	 break;
       default:
-	 Lay_WrongRoleExit ();
+	 Err_WrongRoleExit ();
      }
 
    /***** Begin box and table *****/
@@ -2015,7 +2016,7 @@ void Rec_AllocMemFieldsRecordsCrs (void)
       if (Rec_CheckIfICanEditField (Gbl.Crs.Records.LstFields.Lst[NumField].Visibility))
          /* Allocate memory for the texts of the fields */
          if ((Gbl.Crs.Records.LstFields.Lst[NumField].Text = malloc (Cns_MAX_BYTES_TEXT + 1)) == NULL)
-            Lay_NotEnoughMemoryExit ();
+            Err_NotEnoughMemoryExit ();
   }
 
 /*****************************************************************************/
@@ -3363,11 +3364,11 @@ static void Rec_ShowPhone (struct UsrData *UsrDat,bool ShowData,bool PutForm,
 
    /***** Internal name / id *****/
    if (asprintf (&Name,"Phone%u",NumPhone) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Label to show *****/
    if (asprintf (&Label,"%s %u",Txt_Phone,NumPhone + 1) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Phone *****/
    HTM_TR_Begin (NULL);
@@ -3697,7 +3698,7 @@ Rol_Role_t Rec_GetRoleFromRecordForm (void)
 	 break;
      }
    if (!RoleOK)
-      Lay_WrongRoleExit ();
+      Err_WrongRoleExit ();
    return Role;
   }
 
@@ -3764,7 +3765,7 @@ static void Rec_GetUsrCommentsFromForm (struct UsrData *UsrDat)
   {
    /***** Check if memory is allocated for comments *****/
    if (!UsrDat->Comments)
-      Lay_ShowErrorAndExit ("Can not read comments of a user.");
+      Err_ShowErrorAndExit ("Can not read comments of a user.");
 
    /***** Get the parameter with the comments *****/
    Par_GetParToHTML ("Comments",UsrDat->Comments,Cns_MAX_BYTES_TEXT);
diff --git a/swad_report.c b/swad_report.c
index 3c6eb1b1..b0eb1489 100644
--- a/swad_report.c
+++ b/swad_report.c
@@ -31,6 +31,7 @@
 
 #include "swad_box.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_HTML.h"
@@ -392,7 +393,7 @@ static void Rep_CreateNewReportFile (struct Rep_Report *Report)
              PathUniqueDirL,
              &Gbl.UniqueNameEncrypted[2]);
    if (mkdir (PathUniqueDirR,(mode_t) 0xFFF))
-      Lay_ShowErrorAndExit ("Can not create directory for report.");
+      Err_ShowErrorAndExit ("Can not create directory for report.");
 
    /***** Path of the public file with the report */
    snprintf (Report->FilenameReport,sizeof (Report->FilenameReport),
@@ -401,7 +402,7 @@ static void Rep_CreateNewReportFile (struct Rep_Report *Report)
    snprintf (PathFileReport,sizeof (PathFileReport),"%s/%s",
              PathUniqueDirR,Report->FilenameReport);
    if ((Gbl.F.Rep = fopen (PathFileReport,"wb")) == NULL)
-      Lay_ShowErrorAndExit ("Can not create report file.");
+      Err_ShowErrorAndExit ("Can not create report file.");
 
    /***** Permalink *****/
    snprintf (Permalink,sizeof (Permalink),"%s/%c%c/%s/%s",
@@ -964,7 +965,7 @@ static void Rep_GetMaxHitsPerYear (struct Rep_Report *Report)
    row = mysql_fetch_row (mysql_res);
    if (row[0])	// There are questions
       if (sscanf (row[0],"%lu",&Report->MaxHitsPerYear) != 1)
-         Lay_ShowErrorAndExit ("Error when getting maximum hits.");
+         Err_ShowErrorAndExit ("Error when getting maximum hits.");
 
    /***** Free structure that stores the query result *****/
    DB_FreeMySQLResult (&mysql_res);
@@ -1285,7 +1286,7 @@ static void Rep_ShowMyHitsPerYear (bool AnyCourse,long CrsCod,Rol_Role_t Role,
 
       /* Get the year (in row[0] is the date in YYYY format) */
       if (sscanf (row[0],"%04u",&ReadYear) != 1)
-	 Lay_WrongDateExit ();
+	 Err_WrongDateExit ();
 
       /* Get number hits (in row[1]) */
       if (sscanf (row[1],"%lu",&Report->Hits.Num) != 1)
diff --git a/swad_room.c b/swad_room.c
index bb4c9539..8e7481fb 100644
--- a/swad_room.c
+++ b/swad_room.c
@@ -32,6 +32,7 @@
 #include "swad_box.h"
 #include "swad_building.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_HTML.h"
@@ -381,7 +382,7 @@ void Roo_ChangeMAC (void)
    /***** Get parameters from form *****/
    /* Get room code */
    if ((Roo_EditingRoom->RooCod = Par_GetParToLong ("Cod")) <= 0)
-      Lay_WrongRoomExit ();
+      Err_WrongRoomExit ();
 
    /* Get the old MAC address of the room */
    OldMACnum = MAC_GetMACnumFromForm ("MAC");
@@ -606,7 +607,7 @@ void Roo_GetListRooms (struct Roo_Rooms *Rooms,
       /***** Create list with courses in center *****/
       if ((Rooms->Lst = calloc ((size_t) Rooms->Num,
                                 sizeof (*Rooms->Lst))) == NULL)
-          Lay_NotEnoughMemoryExit ();
+          Err_NotEnoughMemoryExit ();
 
       /***** Get the rooms *****/
       for (NumRoom = 0;
@@ -620,7 +621,7 @@ void Roo_GetListRooms (struct Roo_Rooms *Rooms,
 
          /* Get room code (row[0]) */
          if ((Room->RooCod = Str_ConvertStrCodToLongCod (row[0])) <= 0)
-            Lay_WrongRoomExit ();
+            Err_WrongRoomExit ();
 
 	 switch (WhichData)
 	   {
@@ -1006,7 +1007,7 @@ void Roo_RemoveRoom (void)
 
    /***** Get room code *****/
    if ((Roo_EditingRoom->RooCod = Roo_GetParamRooCod ()) <= 0)
-      Lay_WrongRoomExit ();
+      Err_WrongRoomExit ();
 
    /***** Get data of the room from database *****/
    Roo_GetDataOfRoomByCod (Roo_EditingRoom);
@@ -1059,7 +1060,7 @@ void Roo_ChangeBuilding (void)
    /***** Get parameters from form *****/
    /* Get room code */
    if ((Roo_EditingRoom->RooCod = Roo_GetParamRooCod ()) <= 0)
-      Lay_WrongRoomExit ();
+      Err_WrongRoomExit ();
 
    /* Get room building */
    NewBldCod = Bld_GetParamBldCod ();
@@ -1112,7 +1113,7 @@ void Roo_ChangeFloor (void)
    /***** Get parameters from form *****/
    /* Get room code */
    if ((Roo_EditingRoom->RooCod = Roo_GetParamRooCod ()) <= 0)
-      Lay_WrongRoomExit ();
+      Err_WrongRoomExit ();
 
    /* Get room floor */
    NewFloor = Roo_GetParamFloor ();
@@ -1164,7 +1165,7 @@ void Roo_ChangeType (void)
    /***** Get parameters from form *****/
    /* Get room code */
    if ((Roo_EditingRoom->RooCod = Roo_GetParamRooCod ()) <= 0)
-      Lay_WrongRoomExit ();
+      Err_WrongRoomExit ();
 
    /* Get room type */
    NewType = Roo_GetParamType ();
@@ -1261,7 +1262,7 @@ static void Roo_RenameRoom (Cns_ShrtOrFullName_t ShrtOrFullName)
    /***** Get parameters from form *****/
    /* Get room code */
    if ((Roo_EditingRoom->RooCod = Roo_GetParamRooCod ()) <= 0)
-      Lay_WrongRoomExit ();
+      Err_WrongRoomExit ();
 
    /* Get the new name for the room */
    Par_GetParToText (ParamName,NewClaName,MaxBytes);
@@ -1355,7 +1356,7 @@ void Roo_ChangeCapacity (void)
    /***** Get parameters from form *****/
    /* Get room code */
    if ((Roo_EditingRoom->RooCod = Roo_GetParamRooCod ()) <= 0)
-      Lay_WrongRoomExit ();
+      Err_WrongRoomExit ();
 
    /* Get the seating capacity of the room */
    NewCapacity = (unsigned)
@@ -1656,11 +1657,11 @@ static void Roo_EditingRoomConstructor (void)
   {
    /***** Pointer must be NULL *****/
    if (Roo_EditingRoom != NULL)
-      Lay_WrongRoomExit ();
+      Err_WrongRoomExit ();
 
    /***** Allocate memory for room *****/
    if ((Roo_EditingRoom = malloc (sizeof (*Roo_EditingRoom))) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Reset room *****/
    Roo_EditingRoom->RooCod         = -1L;
diff --git a/swad_scope.c b/swad_scope.c
index 4ded64b8..c6498977 100644
--- a/swad_scope.c
+++ b/swad_scope.c
@@ -28,6 +28,7 @@
 #include <string.h>		// For string functions
 
 #include "swad_config.h"
+#include "swad_error.h"
 #include "swad_global.h"
 #include "swad_HTML.h"
 #include "swad_parameter.h"
@@ -111,7 +112,7 @@ void Sco_PutSelectorScope (const char *ParamName,HTM_SubmitOnChange_t SubmitOnCh
 		  WriteScope = true;
 	       break;
 	    default:
-	       Lay_WrongScopeExit ();
+	       Err_WrongScopeExit ();
 	       break;
 	   }
 
@@ -164,7 +165,7 @@ void Sco_PutSelectorScope (const char *ParamName,HTM_SubmitOnChange_t SubmitOnCh
 			      Gbl.Hierarchy.Crs.ShrtName);
 		  break;
 	       default:
-		  Lay_WrongScopeExit ();
+		  Err_WrongScopeExit ();
 		  break;
 	      }
 	   }
diff --git a/swad_session.c b/swad_session.c
index a4e5ee10..cf572a98 100644
--- a/swad_session.c
+++ b/swad_session.c
@@ -32,6 +32,7 @@
 
 #include "swad_connected.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_global.h"
 #include "swad_parameter.h"
 #include "swad_timeline_database.h"
@@ -84,7 +85,7 @@ void Ses_CreateSession (void)
 
    /***** Check that session is not open *****/
    if (Ses_CheckIfSessionExists (Gbl.Session.Id))
-      Lay_ShowErrorAndExit ("Can not create session.");
+      Err_ShowErrorAndExit ("Can not create session.");
 
    /***** Add session to database *****/
    Ses_InsertSessionInDB ();
diff --git a/swad_setting.c b/swad_setting.c
index 27bcf70f..f260546c 100644
--- a/swad_setting.c
+++ b/swad_setting.c
@@ -35,6 +35,7 @@
 #include "swad_cookie.h"
 #include "swad_database.h"
 #include "swad_date.h"
+#include "swad_error.h"
 #include "swad_figure.h"
 #include "swad_form.h"
 #include "swad_global.h"
@@ -158,7 +159,7 @@ void Set_GetSettingsFromIP (void)
       if (NumRows)
 	{
 	 if (NumRows != 1)
-	    Lay_ShowErrorAndExit ("Internal error while getting settings.");
+	    Err_ShowErrorAndExit ("Internal error while getting settings.");
 
 	 /***** Get settings from database *****/
 	 row = mysql_fetch_row (mysql_res);
diff --git a/swad_statistic.c b/swad_statistic.c
index c1d094dd..7f52525a 100644
--- a/swad_statistic.c
+++ b/swad_statistic.c
@@ -34,6 +34,7 @@
 #include "swad_banner.h"
 #include "swad_box.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_hierarchy.h"
@@ -941,7 +942,7 @@ static void Sta_ShowHits (Sta_GlobalOrCourseAccesses_t GlobalOrCourse)
    /***** Select clicks from the table of log *****/
    /* Allocate memory for the query */
    if ((Query = malloc (Sta_MAX_BYTES_QUERY_ACCESS + 1)) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /* Start the query */
    switch (Stats.ClicksGroupedBy)
@@ -1280,7 +1281,7 @@ static void Sta_ShowHits (Sta_GlobalOrCourseAccesses_t GlobalOrCourse)
 	      {
 	       LengthQuery = LengthQuery + 25 + 10 + 1;
 	       if (LengthQuery > Sta_MAX_BYTES_QUERY_ACCESS - 128)
-                  Lay_ShowErrorAndExit ("Query is too large.");
+                  Err_ShowErrorAndExit ("Query is too large.");
                sprintf (QueryAux,
                         NumUsr ? " OR %s.UsrCod=%ld" :
                                  " AND (%s.UsrCod=%ld",
@@ -1726,7 +1727,7 @@ static void Sta_ShowDetailedAccessesList (const struct Sta_Stats *Stats,
 
       /* Get logged role */
       if (sscanf (row[2],"%u",&RoleFromLog) != 1)
-	 Lay_WrongRoleExit ();
+	 Err_WrongRoleExit ();
 
       HTM_TR_Begin (NULL);
 
@@ -1754,7 +1755,7 @@ static void Sta_ShowDetailedAccessesList (const struct Sta_Stats *Stats,
 
       /* Write the date-time (row[3]) */
       if (asprintf (&Id,"log_date_%u",UniqueId) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       HTM_TD_Begin ("id=\"%s\" class=\"LOG RT COLOR%u\"",Id,Gbl.RowEvenOdd);
       Dat_WriteLocalDateHMSFromUTC (Id,Dat_GetUNIXTimeFromStr (row[3]),
 				    Gbl.Prefs.DateFormat,Dat_SEPARATOR_COMMA,
@@ -1764,7 +1765,7 @@ static void Sta_ShowDetailedAccessesList (const struct Sta_Stats *Stats,
 
       /* Write the action */
       if (sscanf (row[4],"%ld",&ActCod) != 1)
-	 Lay_WrongActionExit ();
+	 Err_WrongActionExit ();
       HTM_TD_Begin ("class=\"LOG LT COLOR%u\"",Gbl.RowEvenOdd);
       if (ActCod >= 0)
          HTM_TxtF ("%s&nbsp;",Act_GetActionText (Act_FromActCodToAction[ActCod]));
@@ -1964,7 +1965,7 @@ static void Sta_ShowNumHitsPerDay (Sta_CountType_t CountType,
 
       /* Get year, month and day (row[0] holds the date in YYYYMMDD format) */
       if (!(Dat_GetDateFromYYYYMMDD (&ReadDate,row[0])))
-	 Lay_WrongDateExit ();
+	 Err_WrongDateExit ();
 
       /* Get number of pages generated (in row[1]) */
       Hits.Num = Str_GetDoubleFromStr (row[1]);
@@ -2172,11 +2173,11 @@ static void Sta_ShowDistrAccessesPerDayAndHour (const struct Sta_Stats *Stats,
 
       /* Get year, month and day (row[0] holds the date in YYYYMMDD format) */
       if (!(Dat_GetDateFromYYYYMMDD (&CurrentReadDate,row[0])))
-	 Lay_WrongDateExit ();
+	 Err_WrongDateExit ();
 
       /* Get the hour (in row[1] is the hour in formato HH) */
       if (sscanf (row[1],"%02u",&ReadHour) != 1)
-	 Lay_WrongDateExit ();
+	 Err_WrongDateExit ();
 
       /* Get number of pages generated (in row[2]) */
       Hits.Num = Str_GetDoubleFromStr (row[2]);
@@ -2542,7 +2543,7 @@ static void Sta_ShowNumHitsPerWeek (Sta_CountType_t CountType,
 
       /* Get year and week (row[0] holds date in YYYYWW format) */
       if (sscanf (row[0],"%04u%02u",&ReadDate.Year,&ReadDate.Week) != 2)
-	 Lay_WrongDateExit ();
+	 Err_WrongDateExit ();
 
       /* Get number of pages generated (in row[1]) */
       Hits.Num = Str_GetDoubleFromStr (row[1]);
@@ -2643,7 +2644,7 @@ static void Sta_ShowNumHitsPerMonth (Sta_CountType_t CountType,
 
       /* Get the year and the month (in row[0] is the date in YYYYMM format) */
       if (sscanf (row[0],"%04u%02u",&ReadDate.Year,&ReadDate.Month) != 2)
-	 Lay_WrongDateExit ();
+	 Err_WrongDateExit ();
 
       /* Get number of pages generated (in row[1]) */
       Hits.Num = Str_GetDoubleFromStr (row[1]);
@@ -2744,7 +2745,7 @@ static void Sta_ShowNumHitsPerYear (Sta_CountType_t CountType,
 
       /* Get the year (in row[0] is the date in YYYY format) */
       if (sscanf (row[0],"%04u",&ReadDate.Year) != 1)
-	 Lay_WrongDateExit ();
+	 Err_WrongDateExit ();
 
       /* Get number of pages generated (in row[1]) */
       Hits.Num = Str_GetDoubleFromStr (row[1]);
@@ -2844,7 +2845,7 @@ static void Sta_ShowNumHitsPerHour (unsigned NumHits,
 	    row = mysql_fetch_row (mysql_res); // Get next result
 	    NumHit++;
 	    if (sscanf (row[0],"%02u",&ReadHour) != 1)   // In row[0] is the date in HH format
-	       Lay_WrongDateExit ();
+	       Err_WrongDateExit ();
 
 	    for (H = Hour;
 		 H < ReadHour;
@@ -2939,7 +2940,7 @@ static void Sta_ShowAverageAccessesPerMinute (unsigned NumHits,MYSQL_RES *mysql_
 	    row = mysql_fetch_row (mysql_res); // Get next result
 	    NumHit++;
 	    if (sscanf (row[0],"%02u%02u",&ReadHour,&MinuteRead) != 2)   // In row[0] is the date in formato HHMM
-	       Lay_WrongDateExit ();
+	       Err_WrongDateExit ();
 	    /* Get number of pages generated */
 	    Hits.Num = Str_GetDoubleFromStr (row[1]);
 	    MinuteDayRead = ReadHour * 60 + MinuteRead;
@@ -3221,7 +3222,7 @@ static void Sta_ShowNumHitsPerPlugin (Sta_CountType_t CountType,
 
       /* Write the plugin */
       if (sscanf (row[0],"%ld",&Plg.PlgCod) != 1)
-	 Lay_WrongPluginExit ();
+	 Err_WrongPluginExit ();
       HTM_TD_Begin ("class=\"LOG RT\"");
       if (Plg_GetDataOfPluginByCod (&Plg))
          HTM_Txt (Plg.Name);
@@ -3277,7 +3278,7 @@ static void Sta_ShowNumHitsPerWSFunction (Sta_CountType_t CountType,
 
       /* Write the plugin */
       if (sscanf (row[0],"%ld",&FunCod) != 1)
-	 Lay_ShowErrorAndExit ("Wrong function code.");
+	 Err_ShowErrorAndExit ("Wrong function code.");
 
       HTM_TD_Begin ("class=\"LOG LT\"");
       HTM_TxtF ("%s&nbsp;",API_GetFunctionNameFromFunCod (FunCod));
@@ -3343,7 +3344,7 @@ static void Sta_ShowNumHitsPerBanner (Sta_CountType_t CountType,
 
       /* Write the banner */
       if (sscanf (row[0],"%ld",&(Ban.BanCod)) != 1)
-	 Lay_WrongBannerExit ();
+	 Err_WrongBannerExit ();
       Ban_GetDataOfBannerByCod (&Ban);
       HTM_TD_Begin ("class=\"LOG LT\"");
       HTM_A_Begin ("href=\"%s\" title=\"%s\" class=\"DAT\" target=\"_blank\"",
@@ -3884,7 +3885,7 @@ static void Sta_DrawBarNumHits (char Color,
       if (BarWidth == 0)
          BarWidth = 1;
       if (asprintf (&Icon,"%c1x1.png",Color) < 0)	// Background
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       HTM_IMG (Cfg_URL_ICON_PUBLIC,Icon,NULL,
 	       "style=\"width:%upx;height:10px;\"",BarWidth);
       free (Icon);
diff --git a/swad_string.c b/swad_string.c
index be1e8031..4ded24f2 100644
--- a/swad_string.c
+++ b/swad_string.c
@@ -34,6 +34,7 @@
 #include <stdlib.h>		// For malloc and free
 #include <string.h>		// For string functions
 
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_ID.h"
@@ -323,7 +324,7 @@ void Str_InsertLinks (char *Txt,unsigned long MaxLength,size_t MaxCharsURLOnScre
 		      ParamsStr);
 	    Anchor1NickLength = strlen (Anchor1Nick);
 	    if ((Links[NumLinks].Anchor1Nick = malloc (Anchor1NickLength + 1)) == NULL)
-	       Lay_NotEnoughMemoryExit ();
+	       Err_NotEnoughMemoryExit ();
 	    strcpy (Links[NumLinks].Anchor1Nick,Anchor1Nick);
 	    Links[NumLinks].Anchor1NickLength = Anchor1NickLength;
 
@@ -336,7 +337,7 @@ void Str_InsertLinks (char *Txt,unsigned long MaxLength,size_t MaxCharsURLOnScre
 			                   Gbl.Form.Id);
 	    Anchor2NickLength = strlen (Anchor2Nick);
 	    if ((Links[NumLinks].Anchor2Nick = malloc (Anchor2NickLength + 1)) == NULL)
-	       Lay_NotEnoughMemoryExit ();
+	       Err_NotEnoughMemoryExit ();
 	    strcpy (Links[NumLinks].Anchor2Nick,Anchor2Nick);
 	    Links[NumLinks].Anchor2NickLength = Anchor2NickLength;
 
@@ -961,7 +962,7 @@ void Str_DoubleNumToStr (char **Str,double Number)
   {
    if (asprintf (Str,"%.15lg",
 		 Number) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
   }
 
 /*****************************************************************************/
@@ -980,7 +981,7 @@ void Str_DoubleNumToStrFewDigits (char **Str,double Number)
    if (FractionaryPart == 0.0)
      {
       if (asprintf (Str,"%.0f",IntegerPart) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
      }
    else
      {
@@ -999,7 +1000,7 @@ void Str_DoubleNumToStrFewDigits (char **Str,double Number)
       else
          Format = "%le";
       if (asprintf (Str,Format,Number) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
      }
   }
 
@@ -1033,7 +1034,7 @@ double Str_GetDoubleFromStr (const char *Str)
 
    /***** Copy source string to temporary string to convert to point *****/
    if (asprintf (&StrPoint,"%s",Str) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** The string is "scanned" in floating point
           (it must have a point, not a comma as decimal separator) *****/
@@ -1149,7 +1150,7 @@ void Str_ChangeFormat (Str_ChangeFrom_t ChangeFrom,Str_ChangeTo_t ChangeTo,
      {
       /***** Allocate memory for a destination string where to do the changes *****/
       if ((StrDst = malloc (MaxLengthStr + 1)) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
 
       /***** Make the change *****/
       for (PtrSrc = Str, PtrDst = StrDst;
@@ -1548,7 +1549,7 @@ void Str_ChangeFormat (Str_ChangeFrom_t ChangeFrom,Str_ChangeTo_t ChangeTo,
 
             /* Check new length of destination string after the copy */
             if (LengthStrDst + LengthSpecStrDst > MaxLengthStr)
-               Lay_ShowErrorAndExit ("Space allocated to string is full.");
+               Err_ShowErrorAndExit ("Space allocated to string is full.");
 
             /* Copy to appropiate place the special character string */
             // strncpy (PtrDst,StrSpecialChar,LengthSpecStrDst);
@@ -1565,7 +1566,7 @@ void Str_ChangeFormat (Str_ChangeFrom_t ChangeFrom,Str_ChangeTo_t ChangeTo,
            {
             /* Check new length of destination string after the copy */
             if (LengthStrDst >= MaxLengthStr)
-               Lay_ShowErrorAndExit ("Space allocated to string is full.");
+               Err_ShowErrorAndExit ("Space allocated to string is full.");
 
             /* Copy char from source to destination and increment pointers */
             *PtrDst++ = *PtrSrc++;
@@ -2503,7 +2504,7 @@ void Str_CopyStrChangingSpaces (const char *StringWithSpaces,char *StringWithout
    *PtrDst = '\0';
 
    if (Length > MaxLength)
-      Lay_ShowErrorAndExit ("Path is too long.");
+      Err_ShowErrorAndExit ("Path is too long.");
   }
 
 /*****************************************************************************/
@@ -2758,7 +2759,7 @@ int Str_ReadFileUntilBoundaryStr (FILE *FileSrc,char *StrDst,
       return 1;
      }
    if (LengthBoundaryStr > Str_MAX_BYTES_BOUNDARY_STR)
-      Lay_ShowErrorAndExit ("Delimiter string too large.");
+      Err_ShowErrorAndExit ("Delimiter string too large.");
    Ptr = StrDst;
 
    StartIndex = 0;
@@ -3018,7 +3019,7 @@ void Str_Copy (char *Dst,const char *Src,size_t DstSize)
       snprintf (ErrorTxt,sizeof (ErrorTxt),
 	        "Trying to copy %zu chars into a %zu-chars buffer.",
                 SrcLength,DstSize);
-      Lay_ShowErrorAndExit (ErrorTxt);
+      Err_ShowErrorAndExit (ErrorTxt);
      }
 
    /***** Copy source into destination *****/
@@ -3043,7 +3044,7 @@ void Str_Concat (char *Dst,const char *Src,size_t DstSize)
      {
       snprintf (ErrorTxt,sizeof (ErrorTxt),"%lu-chars buffer has %lu chars!",
                 DstSize,DstLength);
-      Lay_ShowErrorAndExit (ErrorTxt);
+      Err_ShowErrorAndExit (ErrorTxt);
      }
 
    /***** Check if buffer has enough space for source *****/
@@ -3056,7 +3057,7 @@ void Str_Concat (char *Dst,const char *Src,size_t DstSize)
 	        "Trying to concatenate %zu chars to a %zu-chars buffer"
 	        " with free space for only %zu chars!",
                 SrcLength,DstSize,FreeSpace);
-      Lay_ShowErrorAndExit (ErrorTxt);
+      Err_ShowErrorAndExit (ErrorTxt);
      }
 
    /***** Concatenate ******/
@@ -3076,7 +3077,7 @@ char *Str_BuildStringStr (const char *fmt,const char *Str)
   {
    Str_FreeString ();
    if (asprintf (&Str_String,fmt,Str) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    return Str_String;
   }
@@ -3088,7 +3089,7 @@ char *Str_BuildStringLong (const char *fmt,long Num)
   {
    Str_FreeString ();
    if (asprintf (&Str_String,fmt,Num) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    return Str_String;
   }
@@ -3099,7 +3100,7 @@ char *Str_BuildStringLongStr (long Num,const char *Str)
   {
    Str_FreeString ();
    if (asprintf (&Str_String,"%ld %s",Num,Str) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    return Str_String;
   }
diff --git a/swad_survey.c b/swad_survey.c
index ba0e74b2..7224057a 100644
--- a/swad_survey.c
+++ b/swad_survey.c
@@ -35,6 +35,7 @@
 #include "swad_attendance.h"
 #include "swad_box.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_figure.h"
 #include "swad_form.h"
 #include "swad_global.h"
@@ -434,7 +435,7 @@ void Svy_SeeOneSurvey (void)
 
    /***** Get survey code *****/
    if ((Svy.SvyCod = Svy_GetParamSvyCod ()) <= 0)
-      Lay_WrongSurveyExit ();
+      Err_WrongSurveyExit ();
 
    /***** Show survey *****/
    Svy_ShowOneSurvey (&Surveys,Svy.SvyCod,true);
@@ -500,7 +501,7 @@ static void Svy_ShowOneSurvey (struct Svy_Surveys *Surveys,
    /* Start date/time */
    UniqueId++;
    if (asprintf (&Id,"svy_date_start_%u",UniqueId) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    if (ShowOnlyThisSvyComplete)
       HTM_TD_Begin ("id=\"%s\" class=\"%s LT\"",
 		    Id,
@@ -524,7 +525,7 @@ static void Svy_ShowOneSurvey (struct Svy_Surveys *Surveys,
 
    /* End date/time */
    if (asprintf (&Id,"svy_date_end_%u",UniqueId) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    if (ShowOnlyThisSvyComplete)
       HTM_TD_Begin ("id=\"%s\" class=\"%s LT\"",
 		    Id,
@@ -650,7 +651,7 @@ static void Svy_ShowOneSurvey (struct Svy_Surveys *Surveys,
    switch (Svy.Scope)
      {
       case Hie_Lvl_UNK:	// Unknown
-         Lay_WrongScopeExit ();
+         Err_WrongScopeExit ();
          break;
       case Hie_Lvl_SYS:	// System
          HTM_Txt (Cfg_PLATFORM_SHORT_NAME);
@@ -972,13 +973,13 @@ static void Svy_GetListSurveys (struct Svy_Surveys *Surveys)
 		       Sco_GetDBStrFromScope (Scope),Cods[Scope],
 		       (HiddenAllowed & 1 << Scope) ? "" :
 						      " AND Hidden='N'") < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 	 SubQueryFilled = true;
 	}
       else
         {
 	 if (asprintf (&SubQuery[Scope],"%s","") < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
         }
 
    /* Fill subquery for course */
@@ -1007,7 +1008,7 @@ static void Svy_GetListSurveys (struct Svy_Surveys *Surveys)
 		       (HiddenAllowed & 1 << Hie_Lvl_CRS) ? "" :
 							      " AND Hidden='N'",
 		       Gbl.Usrs.Me.UsrDat.UsrCod) < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
         }
       else	// Gbl.Crs.Grps.WhichGrps == Grp_ALL_GROUPS
         {
@@ -1017,14 +1018,14 @@ static void Svy_GetListSurveys (struct Svy_Surveys *Surveys)
 		       Sco_GetDBStrFromScope (Hie_Lvl_CRS),Cods[Hie_Lvl_CRS],
 		       (HiddenAllowed & 1 << Hie_Lvl_CRS) ? "" :
 							      " AND Hidden='N'") < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
         }
       SubQueryFilled = true;
      }
    else
      {
       if (asprintf (&SubQuery[Hie_Lvl_CRS],"%s","") < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
      }
 
    /* Make query */
@@ -1043,7 +1044,7 @@ static void Svy_GetListSurveys (struct Svy_Surveys *Surveys)
 				OrderBySubQuery[Surveys->SelectedOrder]);
    else
      {
-      Lay_ShowErrorAndExit ("Can not get list of surveys.");
+      Err_ShowErrorAndExit ("Can not get list of surveys.");
       NumRows = 0;	// Not reached. Initialized to avoid warning
      }
 
@@ -1060,7 +1061,7 @@ static void Svy_GetListSurveys (struct Svy_Surveys *Surveys)
       /***** Create list of surveys *****/
       if ((Surveys->LstSvyCods = calloc (NumRows,
                                          sizeof (*Surveys->LstSvyCods))) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
 
       /***** Get the surveys codes *****/
       for (NumSvy = 0;
@@ -1068,7 +1069,7 @@ static void Svy_GetListSurveys (struct Svy_Surveys *Surveys)
 	   NumSvy++)
          /* Get next survey code */
          if ((Surveys->LstSvyCods[NumSvy] = DB_GetNextCode (mysql_res)) < 0)
-            Lay_WrongSurveyExit ();
+            Err_WrongSurveyExit ();
      }
    else
       Surveys->Num = 0;
@@ -1282,7 +1283,7 @@ void Svy_GetDataOfSurveyByCod (struct Svy_Survey *Svy)
 
       /* Get survey scope (row[1]) */
       if ((Svy->Scope = Sco_GetScopeFromDBStr (row[1])) == Hie_Lvl_UNK)
-         Lay_WrongScopeExit ();
+         Err_WrongScopeExit ();
 
       /* Get code of the country, institution, center, degree or course (row[2]) */
       Svy->Cod = Str_ConvertStrCodToLongCod (row[2]);
@@ -1292,7 +1293,7 @@ void Svy_GetDataOfSurveyByCod (struct Svy_Survey *Svy)
 
       /* Get roles (row[4]) */
       if (sscanf (row[4],"%u",&Svy->Roles) != 1)
-      	 Lay_ShowErrorAndExit ("Error when reading roles of survey.");
+      	 Err_ShowErrorAndExit ("Error when reading roles of survey.");
 
       /* Get author of the survey (row[5]) */
       Svy->UsrCod = Str_ConvertStrCodToLongCod (row[5]);
@@ -1320,7 +1321,7 @@ void Svy_GetDataOfSurveyByCod (struct Svy_Survey *Svy)
       switch (Svy->Scope)
         {
 	 case Hie_Lvl_UNK:	// Unknown
-            Lay_WrongScopeExit ();
+            Err_WrongScopeExit ();
 	    break;
 	 case Hie_Lvl_SYS:	// System
             Svy->Status.IBelongToScope = Gbl.Usrs.Me.Logged;
@@ -1525,7 +1526,7 @@ void Svy_GetNotifSurvey (char SummaryStr[Ntf_MAX_BYTES_SUMMARY + 1],
 	{
 	 Length = strlen (row[1]);
 	 if ((*ContentStr = malloc (Length + 1)) == NULL)
-            Lay_NotEnoughMemoryExit ();
+            Err_NotEnoughMemoryExit ();
 	 Str_Copy (*ContentStr,row[1],Length);
 	}
      }
@@ -1574,12 +1575,12 @@ void Svy_AskRemSurvey (void)
 
    /***** Get survey code *****/
    if ((Svy.SvyCod = Svy_GetParamSvyCod ()) <= 0)
-      Lay_WrongSurveyExit ();
+      Err_WrongSurveyExit ();
 
    /***** Get data of the survey from database *****/
    Svy_GetDataOfSurveyByCod (&Svy);
    if (!Svy.Status.ICanEdit)
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Show question and button to remove survey *****/
    Surveys.SvyCod = Svy.SvyCod;
@@ -1613,12 +1614,12 @@ void Svy_RemoveSurvey (void)
 
    /***** Get survey code *****/
    if ((Svy.SvyCod = Svy_GetParamSvyCod ()) <= 0)
-      Lay_WrongSurveyExit ();
+      Err_WrongSurveyExit ();
 
    /***** Get data of the survey from database *****/
    Svy_GetDataOfSurveyByCod (&Svy);
    if (!Svy.Status.ICanEdit)
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Remove all the users in this survey *****/
    DB_QueryDELETE ("can not remove users who are answered a survey",
@@ -1681,12 +1682,12 @@ void Svy_AskResetSurvey (void)
 
    /***** Get survey code *****/
    if ((Svy.SvyCod = Svy_GetParamSvyCod ()) <= 0)
-      Lay_WrongSurveyExit ();
+      Err_WrongSurveyExit ();
 
    /***** Get data of the survey from database *****/
    Svy_GetDataOfSurveyByCod (&Svy);
    if (!Svy.Status.ICanEdit)
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Ask for confirmation of reset *****/
    Ale_ShowAlert (Ale_WARNING,Txt_Do_you_really_want_to_reset_the_survey_X,
@@ -1734,12 +1735,12 @@ void Svy_ResetSurvey (void)
 
    /***** Get survey code *****/
    if ((Svy.SvyCod = Svy_GetParamSvyCod ()) <= 0)
-      Lay_WrongSurveyExit ();
+      Err_WrongSurveyExit ();
 
    /***** Get data of the survey from database *****/
    Svy_GetDataOfSurveyByCod (&Svy);
    if (!Svy.Status.ICanEdit)
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Remove all the users in this survey *****/
    DB_QueryDELETE ("can not remove users who are answered a survey",
@@ -1783,12 +1784,12 @@ void Svy_HideSurvey (void)
 
    /***** Get survey code *****/
    if ((Svy.SvyCod = Svy_GetParamSvyCod ()) <= 0)
-      Lay_WrongSurveyExit ();
+      Err_WrongSurveyExit ();
 
    /***** Get data of the survey from database *****/
    Svy_GetDataOfSurveyByCod (&Svy);
    if (!Svy.Status.ICanEdit)
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Hide survey *****/
    DB_QueryUPDATE ("can not hide survey",
@@ -1820,12 +1821,12 @@ void Svy_UnhideSurvey (void)
 
    /***** Get survey code *****/
    if ((Svy.SvyCod = Svy_GetParamSvyCod ()) <= 0)
-      Lay_WrongSurveyExit ();
+      Err_WrongSurveyExit ();
 
    /***** Get data of the survey from database *****/
    Svy_GetDataOfSurveyByCod (&Svy);
    if (!Svy.Status.ICanEdit)
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
 
    /***** Show survey *****/
    DB_QueryUPDATE ("can not show survey",
@@ -1901,7 +1902,7 @@ void Svy_RequestCreatOrEditSvy (void)
      {
       /***** Put link (form) to create new survey *****/
       if (!Svy_CheckIfICanCreateSvy ())
-         Lay_NoPermissionExit ();
+         Err_NoPermissionExit ();
 
       /* Initialize to empty survey */
       Svy.SvyCod = -1L;
@@ -1926,7 +1927,7 @@ void Svy_RequestCreatOrEditSvy (void)
       /* Get data of the survey from database */
       Svy_GetDataOfSurveyByCod (&Svy);
       if (!Svy.Status.ICanEdit)
-         Lay_NoPermissionExit ();
+         Err_NoPermissionExit ();
 
       /* Get text of the survey from database */
       Svy_GetSurveyTxtFromDB (Svy.SvyCod,Txt);
@@ -2116,7 +2117,7 @@ static void Svy_SetDefaultAndAllowedScope (struct Svy_Survey *Svy)
      }
 
    if (!ICanEdit)
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
   }
 
 /*****************************************************************************/
@@ -2215,7 +2216,7 @@ void Svy_ReceiveFormSurvey (void)
       OldSvy.SvyCod = NewSvy.SvyCod;
       Svy_GetDataOfSurveyByCod (&OldSvy);
       if (!OldSvy.Status.ICanEdit)
-         Lay_NoPermissionExit ();
+         Err_NoPermissionExit ();
       NewSvy.Scope = OldSvy.Scope;
      }
 
@@ -2226,46 +2227,46 @@ void Svy_ReceiveFormSurvey (void)
      {
       case Hie_Lvl_SYS:
 	 if (Gbl.Usrs.Me.Role.Logged != Rol_SYS_ADM)
-	    Lay_WrongScopeExit ();
+	    Err_WrongScopeExit ();
          NewSvy.Scope = Hie_Lvl_SYS;
          NewSvy.Cod = -1L;
          break;
       case Hie_Lvl_CTY:
 	 if (Gbl.Usrs.Me.Role.Logged != Rol_SYS_ADM)
-	    Lay_WrongScopeExit ();
+	    Err_WrongScopeExit ();
 	 NewSvy.Scope = Hie_Lvl_CTY;
 	 NewSvy.Cod = Gbl.Hierarchy.Cty.CtyCod;
          break;
       case Hie_Lvl_INS:
 	 if (Gbl.Usrs.Me.Role.Logged != Rol_SYS_ADM &&
 	     Gbl.Usrs.Me.Role.Logged != Rol_INS_ADM)
-	    Lay_WrongScopeExit ();
+	    Err_WrongScopeExit ();
 	 NewSvy.Scope = Hie_Lvl_INS;
 	 NewSvy.Cod = Gbl.Hierarchy.Ins.InsCod;
          break;
       case Hie_Lvl_CTR:
 	 if (Gbl.Usrs.Me.Role.Logged != Rol_SYS_ADM &&
 	     Gbl.Usrs.Me.Role.Logged != Rol_CTR_ADM)
-	    Lay_WrongScopeExit ();
+	    Err_WrongScopeExit ();
 	 NewSvy.Scope = Hie_Lvl_CTR;
 	 NewSvy.Cod = Gbl.Hierarchy.Ctr.CtrCod;
          break;
       case Hie_Lvl_DEG:
 	 if (Gbl.Usrs.Me.Role.Logged != Rol_SYS_ADM &&
 	     Gbl.Usrs.Me.Role.Logged != Rol_DEG_ADM)
-	    Lay_WrongScopeExit ();
+	    Err_WrongScopeExit ();
 	 NewSvy.Scope = Hie_Lvl_DEG;
 	 NewSvy.Cod = Gbl.Hierarchy.Deg.DegCod;
          break;
       case Hie_Lvl_CRS:
 	 if (Gbl.Usrs.Me.Role.Logged != Rol_SYS_ADM &&
 	     Gbl.Usrs.Me.Role.Logged != Rol_TCH)
-	    Lay_WrongScopeExit ();
+	    Err_WrongScopeExit ();
 	 NewSvy.Scope = Hie_Lvl_CRS;
 	 NewSvy.Cod = Gbl.Hierarchy.Crs.CrsCod;
          break;
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 break;
      }
 
@@ -2686,7 +2687,7 @@ void Svy_RequestEditQuestion (void)
 
    /***** Get survey code *****/
    if ((SvyCod = Svy_GetParamSvyCod ()) <= 0)
-      Lay_WrongSurveyExit ();
+      Err_WrongSurveyExit ();
 
    /* Get the question code */
    SvyQst.QstCod = Svy_GetParamQstCod ();
@@ -2747,7 +2748,7 @@ static void Svy_ShowFormEditOneQst (struct Svy_Surveys *Surveys,
 
          /* Get question index inside survey (row[0]) */
          if (sscanf (row[0],"%u",&(SvyQst->QstInd)) != 1)
-            Lay_WrongQuestionIndexExit ();
+            Err_WrongQuestionIndexExit ();
 
          /* Get the type of answer (row[1]) */
          SvyQst->AnswerType = Svy_ConvertFromStrAnsTypDBToAnsTyp (row[1]);
@@ -2767,7 +2768,7 @@ static void Svy_ShowFormEditOneQst (struct Svy_Surveys *Surveys,
             row = mysql_fetch_row (mysql_res);
 
             if (NumAnswers > Svy_MAX_ANSWERS_PER_QUESTION)
-               Lay_WrongAnswerExit ();
+               Err_WrongAnswerExit ();
             if (!Svy_AllocateTextChoiceAnswer (SvyQst,NumAns))
 	       /* Abort on error */
 	       Ale_ShowAlertsAndExit ();
@@ -2787,7 +2788,7 @@ static void Svy_ShowFormEditOneQst (struct Svy_Surveys *Surveys,
       Surveys->QstCod = SvyQst->QstCod;
 
       if (asprintf (&Title,"%s %u",Txt_Question,SvyQst->QstInd + 1) < 0)	// Question index may be 0, 1, 2, 3,...
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       Box_BoxBegin (NULL,Title,
                     Svy_PutIconToRemoveOneQst,Surveys,
                     NULL,Box_NOT_CLOSABLE);
@@ -3084,7 +3085,7 @@ void Svy_ReceiveQst (void)
    /***** Get parameters from form *****/
    /* Get survey code */
    if ((SvyCod = Svy_GetParamSvyCod ()) <= 0)
-      Lay_WrongSurveyExit ();
+      Err_WrongSurveyExit ();
 
    /* Get question code */
    SvyQst.QstCod = Svy_GetParamQstCod ();
@@ -3270,7 +3271,7 @@ static unsigned Svy_GetNextQuestionIndexInSvy (long SvyCod)
    if (row[0])	// There are questions
      {
       if (sscanf (row[0],"%u",&QstInd) != 1)
-         Lay_ShowErrorAndExit ("Error when getting last question index.");
+         Err_ShowErrorAndExit ("Error when getting last question index.");
       QstInd++;
      }
 
@@ -3363,7 +3364,7 @@ static void Svy_ListSvyQuestions (struct Svy_Surveys *Surveys,
 
          /* row[0] holds the code of the question */
          if (sscanf (row[0],"%ld",&(SvyQst.QstCod)) != 1)
-            Lay_WrongQuestionExit ();
+            Err_WrongQuestionExit ();
 
          HTM_TR_Begin (NULL);
 
@@ -3389,7 +3390,7 @@ static void Svy_ListSvyQuestions (struct Svy_Surveys *Surveys,
 	    /* Write index of question inside survey (row[1]) */
 	    HTM_TD_Begin ("class=\"DAT_SMALL CT COLOR%u\"",Gbl.RowEvenOdd);
 	       if (sscanf (row[1],"%u",&(SvyQst.QstInd)) != 1)
-		  Lay_WrongQuestionIndexExit ();
+		  Err_WrongQuestionIndexExit ();
 	       HTM_Unsigned (SvyQst.QstInd + 1);
 	    HTM_TD_End ();
 
@@ -3488,7 +3489,7 @@ static void Svy_WriteQstStem (const char *Stem)
    /* Convert the stem, that is in HTML, to rigorous HTML */
    Length = strlen (Stem) * Str_MAX_BYTES_PER_CHAR;
    if ((HeadingRigorousHTML = malloc (Length + 1)) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    Str_Copy (HeadingRigorousHTML,Stem,Length);
    Str_ChangeFormat (Str_FROM_HTML,Str_TO_RIGOROUS_HTML,
                      HeadingRigorousHTML,Length,false);
@@ -3523,7 +3524,7 @@ static void Svy_WriteAnswersOfAQst (struct Svy_Survey *Svy,
      {
       /* Check number of answers */
       if (NumAnswers > Svy_MAX_ANSWERS_PER_QUESTION)
-	 Lay_ShowErrorAndExit ("Wrong number of answers.");
+	 Err_ShowErrorAndExit ("Wrong number of answers.");
 
       /* Write one row for each answer */
       HTM_TABLE_BeginPadding (5);
@@ -3536,7 +3537,7 @@ static void Svy_WriteAnswersOfAQst (struct Svy_Survey *Svy,
 
 	 /* Get number of users who have marked this answer (row[1]) */
 	 if (sscanf (row[1],"%u",&NumUsrsThisAnswer) != 1)
-	    Lay_ShowErrorAndExit ("Error when getting number of users who have marked an answer.");
+	    Err_ShowErrorAndExit ("Error when getting number of users who have marked an answer.");
 
 	 /* Convert the answer (row[2]), that is in HTML, to rigorous HTML */
 	 if (!Svy_AllocateTextChoiceAnswer (SvyQst,NumAns))
@@ -3623,13 +3624,13 @@ static void Svy_DrawBarNumUsrs (unsigned NumUsrs,unsigned MaxUsrs)
                     NumUsrs,
                     (unsigned) ((((double) NumUsrs * 100.0) / (double) MaxUsrs) + 0.5),
                     Txt_of_PART_OF_A_TOTAL,MaxUsrs) < 0)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
      }
    else
      {
       if (asprintf (&Title,"0&nbsp;(0%%&nbsp;%s&nbsp;%u)",
                     Txt_of_PART_OF_A_TOTAL,MaxUsrs) < 0)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
      }
 
    HTM_TD_Begin ("class=\"DAT LT\" style=\"width:%upx;\"",Svy_MAX_BAR_WIDTH + 125);
@@ -3696,11 +3697,11 @@ void Svy_RequestRemoveQst (void)
    /***** Get parameters from form *****/
    /* Get survey code */
    if ((SvyCod = Svy_GetParamSvyCod ()) <= 0)
-      Lay_WrongSurveyExit ();
+      Err_WrongSurveyExit ();
 
    /* Get question code */
    if ((SvyQst.QstCod = Svy_GetParamQstCod ()) < 0)
-      Lay_WrongQuestionExit ();
+      Err_WrongQuestionExit ();
 
    /* Get question index */
    SvyQst.QstInd = Svy_GetQstIndFromQstCod (SvyQst.QstCod);
@@ -3738,11 +3739,11 @@ void Svy_RemoveQst (void)
    /***** Get parameters from form *****/
    /* Get survey code */
    if ((SvyCod = Svy_GetParamSvyCod ()) <= 0)
-      Lay_WrongSurveyExit ();
+      Err_WrongSurveyExit ();
 
    /* Get question code */
    if ((SvyQst.QstCod = Svy_GetParamQstCod ()) <= 0)
-      Lay_WrongQuestionExit ();
+      Err_WrongQuestionExit ();
 
    /* Get question index */
    SvyQst.QstInd = Svy_GetQstIndFromQstCod (SvyQst.QstCod);
@@ -3757,7 +3758,7 @@ void Svy_RemoveQst (void)
 		   " WHERE QstCod=%ld",
 		   SvyQst.QstCod);
    if (!mysql_affected_rows (&Gbl.mysql))
-      Lay_WrongQuestionExit ();
+      Err_WrongQuestionExit ();
 
    /* Change index of questions greater than this */
    DB_QueryUPDATE ("can not update indexes of questions",
@@ -3791,7 +3792,7 @@ void Svy_ReceiveSurveyAnswers (void)
 
    /***** Get survey code *****/
    if ((Svy.SvyCod = Svy_GetParamSvyCod ()) <= 0)
-      Lay_WrongSurveyExit ();
+      Err_WrongSurveyExit ();
 
    /***** Get data of the survey from database *****/
    Svy_GetDataOfSurveyByCod (&Svy);
@@ -3844,7 +3845,7 @@ static void Svy_ReceiveAndStoreUserAnswersToASurvey (long SvyCod)
         {
          /* Get next question */
          if ((QstCod = DB_GetNextCode (mysql_res)) <= 0)
-            Lay_WrongQuestionExit ();
+            Err_WrongQuestionExit ();
 
          /* Get possible parameter with the user's answer */
          snprintf (ParamName,sizeof (ParamName),"Ans%010u",(unsigned) QstCod);
@@ -3863,7 +3864,7 @@ static void Svy_ReceiveAndStoreUserAnswersToASurvey (long SvyCod)
         }
      }
    else		// This survey has no questions
-      Lay_ShowErrorAndExit ("Error: this survey has no questions.");
+      Err_ShowErrorAndExit ("Error: this survey has no questions.");
 
    /***** Free structure that stores the query result *****/
    DB_FreeMySQLResult (&mysql_res);
@@ -4116,20 +4117,20 @@ unsigned Svy_GetNumCrsSurveys (Hie_Lvl_Level_t Scope,unsigned *NumNotif)
 			 Gbl.Hierarchy.Crs.CrsCod);
          break;
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 break;
      }
 
    /***** Get number of surveys *****/
    row = mysql_fetch_row (mysql_res);
    if (sscanf (row[0],"%u",&NumSurveys) != 1)
-      Lay_ShowErrorAndExit ("Error when getting number of surveys.");
+      Err_ShowErrorAndExit ("Error when getting number of surveys.");
 
    /***** Get number of notifications by email *****/
    if (row[1])
      {
       if (sscanf (row[1],"%u",NumNotif) != 1)
-         Lay_ShowErrorAndExit ("Error when getting number of notifications of surveys.");
+         Err_ShowErrorAndExit ("Error when getting number of notifications of surveys.");
      }
    else
       *NumNotif = 0;
@@ -4239,7 +4240,7 @@ double Svy_GetNumQstsPerCrsSurvey (Hie_Lvl_Level_t Scope)
 					       " GROUP BY svy_questions.SvyCod) AS NumQstsTable",
 				      Sco_GetDBStrFromScope (Hie_Lvl_CRS),Gbl.Hierarchy.Crs.CrsCod);
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 return 0.0;	// Not reached
      }
   }
diff --git a/swad_syllabus.c b/swad_syllabus.c
index 0cc13810..70b47ba9 100644
--- a/swad_syllabus.c
+++ b/swad_syllabus.c
@@ -37,6 +37,7 @@
 #include "swad_changelog.h"
 #include "swad_config.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_forum.h"
 #include "swad_global.h"
@@ -350,7 +351,7 @@ static void Syl_SetSyllabusTypeFromAction (struct Syl_Syllabus *Syllabus)
 	 Gbl.Crs.Info.Type = Inf_PRACTICALS;
          break;
       default:
-	 Lay_WrongActionExit ();
+	 Err_WrongActionExit ();
 	 break;
      }
   }
@@ -381,7 +382,7 @@ void Syl_LoadListItemsSyllabusIntoMemory (struct Syl_Syllabus *Syllabus,
 
    /***** Go to the start of the list of items *****/
    if (!Str_FindStrInFile (Gbl.F.XML,"<lista>",Str_NO_SKIP_HTML_COMMENTS))
-      Lay_WrongSyllabusFormatExit ();
+      Err_WrongSyllabusFormatExit ();
 
    /***** Save the position of the start of the list *****/
    PostBeginList = ftell (Gbl.F.XML);
@@ -394,7 +395,7 @@ void Syl_LoadListItemsSyllabusIntoMemory (struct Syl_Syllabus *Syllabus,
    /***** Allocate memory for the list of items *****/
    if ((Syl_LstItemsSyllabus.Lst = calloc (Syl_LstItemsSyllabus.NumItems + 1,
                                            sizeof (*Syl_LstItemsSyllabus.Lst))) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Return to the start of the list *****/
    fseek (Gbl.F.XML,PostBeginList,SEEK_SET);
@@ -429,7 +430,7 @@ void Syl_LoadListItemsSyllabusIntoMemory (struct Syl_Syllabus *Syllabus,
 	{
 	 /* Go to the start of the item */
 	 if (!Str_FindStrInFile (Gbl.F.XML,"<item",Str_NO_SKIP_HTML_COMMENTS))
-	    Lay_WrongSyllabusFormatExit ();
+	    Err_WrongSyllabusFormatExit ();
 
 	 /* Get the level */
 	 Syl_LstItemsSyllabus.Lst[NumItem].Level = Syl_ReadLevelItemSyllabus ();
@@ -454,10 +455,10 @@ void Syl_LoadListItemsSyllabusIntoMemory (struct Syl_Syllabus *Syllabus,
 	 if (Result == 0) // Str too long
 	   {
 	    if (!Str_FindStrInFile (Gbl.F.XML,"</item>",Str_NO_SKIP_HTML_COMMENTS)) // End the search
-	       Lay_WrongSyllabusFormatExit ();
+	       Err_WrongSyllabusFormatExit ();
 	   }
 	 else if (Result == -1)
-	    Lay_WrongSyllabusFormatExit ();
+	    Err_WrongSyllabusFormatExit ();
 	}
 
    /***** Close the file with the syllabus *****/
@@ -507,12 +508,12 @@ int Syl_ReadLevelItemSyllabus (void)
    char StrlLevel[11 + 1];
 
    if (!Str_FindStrInFile (Gbl.F.XML,"nivel=\"",Str_NO_SKIP_HTML_COMMENTS))
-      Lay_WrongSyllabusFormatExit ();
+      Err_WrongSyllabusFormatExit ();
    if (Str_ReadFileUntilBoundaryStr (Gbl.F.XML,StrlLevel,"\"",1,
    	                             (unsigned long long) (11 + 1)) != 1)
-      Lay_WrongSyllabusFormatExit ();
+      Err_WrongSyllabusFormatExit ();
    if (sscanf (StrlLevel,"%d",&Level) != 1)
-      Lay_WrongSyllabusFormatExit ();
+      Err_WrongSyllabusFormatExit ();
    Str_FindStrInFile (Gbl.F.XML,">",Str_NO_SKIP_HTML_COMMENTS);
    if (Level < 1)
       Level = 1;
@@ -1400,18 +1401,18 @@ static void Syl_OpenSyllabusFile (const struct Syl_Syllabus *Syllabus,
 	{
 	 /* Can't open the file */
 	 if (!Fil_CheckIfPathExists (Syllabus->PathDir)) // Strange error, since it is just created
-	    Lay_ShowErrorAndExit ("Can not open syllabus file.");
+	    Err_ShowErrorAndExit ("Can not open syllabus file.");
 	 else
 	   {
 	    /* Create a new empty syllabus */
 	    if ((Gbl.F.XML = fopen (PathFile,"wb")) == NULL)
-	       Lay_ShowErrorAndExit ("Can not create syllabus file.");
+	       Err_ShowErrorAndExit ("Can not create syllabus file.");
 	    Syl_WriteStartFileSyllabus (Gbl.F.XML);
 	    Syl_WriteEndFileSyllabus (Gbl.F.XML);
 	    Fil_CloseXMLFile ();
 	    /* Open of new the file for reading */
 	    if ((Gbl.F.XML = fopen (PathFile,"rb")) == NULL)
-	       Lay_ShowErrorAndExit ("Can not open syllabus file.");
+	       Err_ShowErrorAndExit ("Can not open syllabus file.");
 	   }
 	}
      }
diff --git a/swad_system_config.c b/swad_system_config.c
index 60bf9c5f..27f5b6ef 100644
--- a/swad_system_config.c
+++ b/swad_system_config.c
@@ -36,6 +36,7 @@
 #include "swad_config.h"
 #include "swad_course.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_figure_cache.h"
 #include "swad_form.h"
 #include "swad_help.h"
@@ -210,7 +211,7 @@ static void SysCfg_GetCoordAndZoom (struct Coordinates *Coord,unsigned *Zoom)
 		  " FROM ctr_centers"
 		 " WHERE Latitude<>0"
 		   " AND Longitude<>0") < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    Map_GetCoordAndZoom (Coord,Zoom,Query);
    free (Query);
   }
diff --git a/swad_tag.c b/swad_tag.c
index aeb8d545..e0e5e27a 100644
--- a/swad_tag.c
+++ b/swad_tag.c
@@ -32,6 +32,7 @@
 
 #include "swad_action.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_tag.h"
@@ -230,7 +231,7 @@ static long Tag_GetParamTagCode (void)
 
    /***** Get tag code *****/
    if ((TagCod = Par_GetParToLong ("TagCod")) <= 0)
-      Lay_WrongTagExit ();
+      Err_WrongTagExit ();
 
    return TagCod;
   }
@@ -286,7 +287,7 @@ void Tag_RenameTag (void)
 		     change old tag to new tag in tst_question_tags *****/
 	    /* Get tag code of the old tag */
 	    if ((OldTagCod = Tag_GetTagCodFromTagTxt (OldTagTxt)) <= 0)
-	       Lay_WrongTagExit ();
+	       Err_WrongTagExit ();
 
 	    /* Create a temporary table with all the question codes
 	       that had the new tag as one of their tags */
@@ -578,7 +579,7 @@ void Tag_ShowFormEditTags (void)
 	 row[2] TagHidden
 	 */
          if ((TagCod = Str_ConvertStrCodToLongCod (row[0])) <= 0)
-            Lay_WrongTagExit ();
+            Err_WrongTagExit ();
 
          HTM_TR_Begin (NULL);
 
diff --git a/swad_test.c b/swad_test.c
index 8eb72187..28e69739 100644
--- a/swad_test.c
+++ b/swad_test.c
@@ -40,6 +40,7 @@
 #include "swad_action.h"
 #include "swad_box.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_exam_set.h"
 #include "swad_figure.h"
 #include "swad_form.h"
@@ -435,7 +436,7 @@ void Tst_ReceiveTestDraft (void)
    /* Get test exam code from form */
    TstPrn_ResetPrint (&Print);
    if ((Print.PrnCod = TstPrn_GetParamPrnCod ()) <= 0)
-      Lay_WrongTestExit ();
+      Err_WrongTestExit ();
 
    /* Get number of this test from form */
    NumTst = Tst_GetParamNumTst ();
@@ -491,7 +492,7 @@ void Tst_AssessTest (void)
    /* Get test exam code from form */
    TstPrn_ResetPrint (&Print);
    if ((Print.PrnCod = TstPrn_GetParamPrnCod ()) <= 0)
-      Lay_WrongTestExit ();
+      Err_WrongTestExit ();
 
    /* Get number of this test from form */
    NumTst = Tst_GetParamNumTst ();
@@ -619,7 +620,7 @@ static bool Tst_CheckIfNextTstAllowed (void)
             TimeNextTestUTC = Dat_GetUNIXTimeFromStr (row[1]);
      }
    else
-      Lay_ShowErrorAndExit ("Error when reading date of next allowed access to test.");
+      Err_ShowErrorAndExit ("Error when reading date of next allowed access to test.");
 
    /***** Free structure that stores the query result *****/
    DB_FreeMySQLResult (&mysql_res);
@@ -677,7 +678,7 @@ static unsigned Tst_GetNumExamsGeneratedByMe (void)
             NumExamsGeneratedByMe = 0;
         }
       else
-         Lay_ShowErrorAndExit ("Error when getting number of hits to test.");
+         Err_ShowErrorAndExit ("Error when getting number of hits to test.");
 
       /***** Free structure that stores the query result *****/
       DB_FreeMySQLResult (&mysql_res);
@@ -818,7 +819,7 @@ void Tst_WriteQstStem (const char *Stem,const char *ClassStem,bool Visible)
 	 /* Convert the stem, that is in HTML, to rigorous HTML */
 	 StemLength = strlen (Stem) * Str_MAX_BYTES_PER_CHAR;
 	 if ((StemRigorousHTML = malloc (StemLength + 1)) == NULL)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 	 Str_Copy (StemRigorousHTML,Stem,StemLength);
 
 	 Str_ChangeFormat (Str_FROM_HTML,Str_TO_RIGOROUS_HTML,
@@ -917,7 +918,7 @@ void Tst_WriteQstFeedback (const char *Feedback,const char *ClassFeedback)
 	 /***** Convert the feedback, that is in HTML, to rigorous HTML *****/
 	 FeedbackLength = strlen (Feedback) * Str_MAX_BYTES_PER_CHAR;
 	 if ((FeedbackRigorousHTML = malloc (FeedbackLength + 1)) == NULL)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 	 Str_Copy (FeedbackRigorousHTML,Feedback,FeedbackLength);
 	 Str_ChangeFormat (Str_FROM_HTML,Str_TO_RIGOROUS_HTML,
 			   FeedbackRigorousHTML,FeedbackLength,false);
@@ -1753,7 +1754,7 @@ static void Tst_GetQuestions (struct Tst_Test *Test,MYSQL_RES **mysql_res)
 
    /***** Allocate space for query *****/
    if ((Query = malloc (Tst_MAX_BYTES_QUERY_TEST + 1)) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Select questions *****/
    /* Start query */
@@ -1794,7 +1795,7 @@ static void Tst_GetQuestions (struct Tst_Test *Test,MYSQL_RES **mysql_res)
          Par_GetNextStrUntilSeparParamMult (&Ptr,TagText,Tag_MAX_BYTES_TAG);
          LengthQuery = LengthQuery + 35 + strlen (TagText) + 1;
          if (LengthQuery > Tst_MAX_BYTES_QUERY_TEST - 256)
-            Lay_ShowErrorAndExit ("Query size exceed.");
+            Err_ShowErrorAndExit ("Query size exceed.");
          Str_Concat (Query,
                      NumItemInList ? " OR tst_tags.TagTxt='" :
                                      " AND (tst_tags.TagTxt='",
@@ -1818,7 +1819,7 @@ static void Tst_GetQuestions (struct Tst_Test *Test,MYSQL_RES **mysql_res)
 	 AnsType = Tst_ConvertFromUnsignedStrToAnsTyp (UnsignedStr);
          LengthQuery = LengthQuery + 35 + strlen (Tst_StrAnswerTypesDB[AnsType]) + 1;
          if (LengthQuery > Tst_MAX_BYTES_QUERY_TEST - 256)
-            Lay_ShowErrorAndExit ("Query size exceed.");
+            Err_ShowErrorAndExit ("Query size exceed.");
          Str_Concat (Query,
                      NumItemInList ? " OR tst_questions.AnsType='" :
                                      " AND (tst_questions.AnsType='",
@@ -1894,11 +1895,11 @@ static void Tst_GetQuestionsForNewTestFromDB (struct Tst_Test *Test,
    /***** Trivial check: number of questions *****/
    if (Test->NumQsts == 0 ||
        Test->NumQsts > TstCfg_MAX_QUESTIONS_PER_TEST)
-      Lay_ShowErrorAndExit ("Wrong number of questions.");
+      Err_ShowErrorAndExit ("Wrong number of questions.");
 
    /***** Allocate space for query *****/
    if ((Query = malloc (Tst_MAX_BYTES_QUERY_TEST + 1)) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Select questions without hidden tags *****/
    /* Start query */
@@ -1935,7 +1936,7 @@ static void Tst_GetQuestionsForNewTestFromDB (struct Tst_Test *Test,
          Par_GetNextStrUntilSeparParamMult (&Ptr,TagText,Tag_MAX_BYTES_TAG);
          LengthQuery = LengthQuery + 35 + strlen (TagText) + 1;
          if (LengthQuery > Tst_MAX_BYTES_QUERY_TEST - 128)
-            Lay_ShowErrorAndExit ("Query size exceed.");
+            Err_ShowErrorAndExit ("Query size exceed.");
          Str_Concat (Query,
                      NumItemInList ? " OR tst_tags.TagTxt='" :
                                      " AND (tst_tags.TagTxt='",
@@ -1959,7 +1960,7 @@ static void Tst_GetQuestionsForNewTestFromDB (struct Tst_Test *Test,
 	 AnswerType = Tst_ConvertFromUnsignedStrToAnsTyp (UnsignedStr);
          LengthQuery = LengthQuery + 35 + strlen (Tst_StrAnswerTypesDB[AnswerType]) + 1;
          if (LengthQuery > Tst_MAX_BYTES_QUERY_TEST - 128)
-            Lay_ShowErrorAndExit ("Query size exceed.");
+            Err_ShowErrorAndExit ("Query size exceed.");
          Str_Concat (Query,
                      NumItemInList ? " OR tst_questions.AnsType='" :
                                      " AND (tst_questions.AnsType='",
@@ -2000,7 +2001,7 @@ static void Tst_GetQuestionsForNewTestFromDB (struct Tst_Test *Test,
 
       /* Get question code (row[0]) */
       if ((Print->PrintedQuestions[NumQst].QstCod = Str_ConvertStrCodToLongCod (row[0])) < 0)
-	 Lay_ShowErrorAndExit ("Wrong code of question.");
+	 Err_ShowErrorAndExit ("Wrong code of question.");
 
       /* Get answer type (row[1]) */
       AnswerType = Tst_ConvertFromStrAnsTypDBToAnsTyp (row[1]);
@@ -2086,7 +2087,7 @@ void Tst_GenerateChoiceIndexes (struct TstPrn_PrintedQuestion *PrintedQuestion,
       else
          ErrorInIndex = true;
       if (ErrorInIndex)
-         Lay_ShowErrorAndExit ("Wrong index of answer.");
+         Err_ShowErrorAndExit ("Wrong index of answer.");
 
       snprintf (StrInd,sizeof (StrInd),NumOpt ? ",%u" :
 						"%u",Index);
@@ -2169,7 +2170,7 @@ static void Tst_ListOneOrMoreQuestionsForEdition (struct Tst_Test *Test,
       /***** Get question code (row[0]) *****/
       row = mysql_fetch_row (mysql_res);
       if ((Test->Question.QstCod = Str_ConvertStrCodToLongCod (row[0])) < 0)
-         Lay_WrongQuestionExit ();
+         Err_WrongQuestionExit ();
 
       /***** Write question row *****/
       Tst_WriteQuestionListing (Test,NumQst);
@@ -2290,7 +2291,7 @@ static void Tst_WriteQuestionListing (struct Tst_Test *Test,unsigned NumQst)
 
       /* Date (row[0] has the UTC date-time) */
       if (asprintf (&Id,"tst_date_%u",++UniqueId) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       HTM_TD_Begin ("id=\"%s\" class=\"DAT_SMALL CT COLOR%u\"",
 		    Id,Gbl.RowEvenOdd);
       Dat_WriteLocalDateHMSFromUTC (Id,Test->Question.EditTime,
@@ -2432,7 +2433,7 @@ static void Tst_ListOneOrMoreQuestionsForSelectionForSet (struct Exa_Exams *Exam
       /* Get question code (row[0]) */
       row = mysql_fetch_row (mysql_res);
       if ((Question.QstCod = Str_ConvertStrCodToLongCod (row[0])) < 0)
-         Lay_WrongQuestionExit ();
+         Err_WrongQuestionExit ();
 
       /* Write question row */
       Tst_WriteQuestionRowForSelection (NumQst,&Question);
@@ -2517,7 +2518,7 @@ static void Tst_ListOneOrMoreQuestionsForSelectionForGame (struct Gam_Games *Gam
       /* Get question code (row[0]) */
       row = mysql_fetch_row (mysql_res);
       if ((Question.QstCod = Str_ConvertStrCodToLongCod (row[0])) < 0)
-         Lay_WrongQuestionExit ();
+         Err_WrongQuestionExit ();
 
       /* Write question row */
       Tst_WriteQuestionRowForSelection (NumQst,&Question);
@@ -2593,7 +2594,7 @@ static void Tst_WriteQuestionRowForSelection (unsigned NumQst,
 
       /* Write the date (row[0] has the UTC date-time) */
       if (asprintf (&Id,"tst_date_%u",++UniqueId) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       HTM_TD_Begin ("id=\"%s\" class=\"DAT_SMALL CT COLOR%u\">",
 		    Id,Gbl.RowEvenOdd);
       Dat_WriteLocalDateHMSFromUTC (Id,Question->EditTime,
@@ -2903,7 +2904,7 @@ void Tst_WriteParamQstCod (unsigned NumQst,long QstCod)
 void Tst_CheckIfNumberOfAnswersIsOne (const struct Tst_Question *Question)
   {
    if (Question->Answer.NumOptions != 1)
-      Lay_WrongAnswerExit ();
+      Err_WrongAnswerExit ();
   }
 
 /*****************************************************************************/
@@ -2985,7 +2986,7 @@ static bool Tst_GetParamsTst (struct Tst_Test *Test,
 
    /* Get the tags */
    if ((Test->Tags.List = malloc (Tag_MAX_BYTES_TAGS_LIST + 1)) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    Par_GetParMultiToText ("ChkTag",Test->Tags.List,Tag_MAX_BYTES_TAGS_LIST);
 
    /* Check number of tags selected */
@@ -3148,7 +3149,7 @@ unsigned Tst_CountNumQuestionsInList (const char *ListQuestions)
      {
       Par_GetNextStrUntilSeparParamMult (&Ptr,LongStr,Cns_MAX_DECIMAL_DIGITS_LONG);
       if (sscanf (LongStr,"%ld",&QstCod) != 1)
-         Lay_WrongQuestionExit ();
+         Err_WrongQuestionExit ();
       NumQuestions++;
      }
    return NumQuestions;
@@ -3519,7 +3520,7 @@ static void Tst_PutFormEditOneQst (struct Tst_Question *Question)
 	                                "",
 	           NumOpt);
       if (asprintf (&Title,"%s %c)",Txt_Expand,'a' + (char) NumOpt) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       Ico_PutIcon ("caret-right.svg",Title,"ICO16x16");
       free (Title);
       HTM_A_End ();
@@ -3532,7 +3533,7 @@ static void Tst_PutFormEditOneQst (struct Tst_Question *Question)
 	                                " style=\"display:none;\"",	// Answer does not have content ==> Hide icon
                    NumOpt);
       if (asprintf (&Title,"%s %c)",Txt_Contract,'a' + (char) NumOpt) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       Ico_PutIcon ("caret-down.svg",Title,"ICO16x16");
       free (Title);
       HTM_A_End ();
@@ -3658,11 +3659,11 @@ void Tst_QstConstructor (struct Tst_Question *Question)
 
    /***** Allocate memory for stem and feedback *****/
    if ((Question->Stem = malloc (Cns_MAX_BYTES_TEXT + 1)) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    Question->Stem[0] = '\0';
 
    if ((Question->Feedback = malloc (Cns_MAX_BYTES_TEXT + 1)) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    Question->Feedback[0] = '\0';
 
    /***** Initialize answers *****/
@@ -3944,7 +3945,7 @@ bool Tst_GetQstDataFromDB (struct Tst_Question *Question)
 	       break;
 	    case Tst_ANS_FLOAT:
 	       if (Question->Answer.NumOptions != 2)
-		  Lay_WrongAnswerExit ();
+		  Err_WrongAnswerExit ();
 	       Question->Answer.FloatingPoint[NumOpt] = Str_GetDoubleFromStr (row[1]);
 	       break;
 	    case Tst_ANS_TRUE_FALSE:
@@ -3956,7 +3957,7 @@ bool Tst_GetQstDataFromDB (struct Tst_Question *Question)
 	    case Tst_ANS_TEXT:
 	       /* Check number of options */
 	       if (Question->Answer.NumOptions > Tst_MAX_OPTIONS_PER_QUESTION)
-		  Lay_WrongAnswerExit ();
+		  Err_WrongAnswerExit ();
 
 	       /*  Allocate space for text and feedback */
 	       if (!Tst_AllocateTextChoiceAnswer (Question,NumOpt))
@@ -4067,9 +4068,9 @@ static Tst_AnswerType_t Tst_ConvertFromUnsignedStrToAnsTyp (const char *Unsigned
    unsigned AnsType;
 
    if (sscanf (UnsignedStr,"%u",&AnsType) != 1)
-      Lay_ShowErrorAndExit ("Wrong type of answer. 2");
+      Err_ShowErrorAndExit ("Wrong type of answer. 2");
    if (AnsType >= Tst_NUM_ANS_TYPES)
-      Lay_ShowErrorAndExit ("Wrong type of answer. 3");
+      Err_ShowErrorAndExit ("Wrong type of answer. 3");
    return (Tst_AnswerType_t) AnsType;
   }
 
@@ -4142,7 +4143,7 @@ static void Tst_GetQstFromForm (struct Tst_Question *Question)
 						     Tst_NUM_ANS_TYPES - 1,
 						     (unsigned long) Tst_ANS_UNKNOWN);
    if (Question->Answer.Type == Tst_ANS_UNKNOWN)
-      Lay_WrongAnswerExit ();
+      Err_WrongAnswerExit ();
 
    /***** Get question tags *****/
    for (NumTag = 0;
@@ -4279,9 +4280,9 @@ static void Tst_GetQstFromForm (struct Tst_Question *Question)
               {
   	       Par_GetNextStrUntilSeparParamMult (&Ptr,UnsignedStr,Cns_MAX_DECIMAL_DIGITS_UINT);
 	       if (sscanf (UnsignedStr,"%u",&NumCorrectAns) != 1)
-	          Lay_WrongAnswerExit ();
+	          Err_WrongAnswerExit ();
                if (NumCorrectAns >= Tst_MAX_OPTIONS_PER_QUESTION)
-	          Lay_WrongAnswerExit ();
+	          Err_WrongAnswerExit ();
                Question->Answer.Options[NumCorrectAns].Correct = true;
               }
            }
@@ -4530,7 +4531,7 @@ bool Tst_CheckIfQuestionExistsInDB (struct Tst_Question *Question)
         {
 	 /* Get question code */
          if ((Question->QstCod = DB_GetNextCode (mysql_res_qst)) < 0)
-            Lay_WrongQuestionExit ();
+            Err_WrongQuestionExit ();
 
          /* Get answers from this question */
          NumOptsExistingQstInDB =
@@ -4714,7 +4715,7 @@ void Tst_RemoveSelectedQsts (void)
 	 /* Get question code (row[0]) */
 	 row = mysql_fetch_row (mysql_res);
 	 if ((QstCod = Str_ConvertStrCodToLongCod (row[0])) < 0)
-	    Lay_WrongQuestionExit ();
+	    Err_WrongQuestionExit ();
 
 	 /* Remove test question from database */
 	 Tst_RemoveOneQstFromDB (Gbl.Hierarchy.Crs.CrsCod,QstCod);
@@ -4759,7 +4760,7 @@ void Tst_RequestRemoveOneQst (void)
    /* Get the question code */
    Test.Question.QstCod = Tst_GetParamQstCod ();
    if (Test.Question.QstCod <= 0)
-      Lay_WrongQuestionExit ();
+      Err_WrongQuestionExit ();
 
    /* Get a parameter that indicates whether it's necessary
       to continue listing the rest of questions */
@@ -4768,7 +4769,7 @@ void Tst_RequestRemoveOneQst (void)
    /* Get other parameters */
    if (!EditingOnlyThisQst)
       if (!Tst_GetParamsTst (&Test,Tst_EDIT_TEST))
-	 Lay_ShowErrorAndExit ("Wrong test parameters.");
+	 Err_ShowErrorAndExit ("Wrong test parameters.");
 
    /***** Show question and button to remove question *****/
    if (EditingOnlyThisQst)
@@ -4820,7 +4821,7 @@ void Tst_RemoveOneQst (void)
    /***** Get the question code *****/
    QstCod = Tst_GetParamQstCod ();
    if (QstCod <= 0)
-      Lay_WrongQuestionExit ();
+      Err_WrongQuestionExit ();
 
    /***** Get a parameter that indicates whether it's necessary
           to continue listing the rest of questions ******/
@@ -4862,7 +4863,7 @@ static void Tst_RemoveOneQstFromDB (long CrsCod,long QstCod)
 		   CrsCod);
 
    if (!mysql_affected_rows (&Gbl.mysql))
-      Lay_WrongQuestionExit ();
+      Err_WrongQuestionExit ();
   }
 
 /*****************************************************************************/
@@ -4883,7 +4884,7 @@ void Tst_ChangeShuffleQst (void)
    /***** Get the question code *****/
    Test.Question.QstCod = Tst_GetParamQstCod ();
    if (Test.Question.QstCod <= 0)
-      Lay_WrongQuestionExit ();
+      Err_WrongQuestionExit ();
 
    /***** Get a parameter that indicates whether it's necessary to continue listing the rest of questions ******/
    EditingOnlyThisQst = Par_GetParToBool ("OnlyThisQst");
@@ -5503,23 +5504,23 @@ static unsigned Tst_GetNumTstQuestions (Hie_Lvl_Level_t Scope,Tst_AnswerType_t A
 			    Tst_StrAnswerTypesDB[AnsType]);
          break;
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 break;
      }
 
    /***** Get number of questions *****/
    row = mysql_fetch_row (mysql_res);
    if (sscanf (row[0],"%u",&(Stats->NumQsts)) != 1)
-      Lay_ShowErrorAndExit ("Error when getting number of test questions.");
+      Err_ShowErrorAndExit ("Error when getting number of test questions.");
 
    if (Stats->NumQsts)
      {
       if (sscanf (row[1],"%lu",&(Stats->NumHits)) != 1)
-         Lay_ShowErrorAndExit ("Error when getting total number of hits in test questions.");
+         Err_ShowErrorAndExit ("Error when getting total number of hits in test questions.");
 
       Str_SetDecimalPointToUS ();	// To get the decimal point as a dot
       if (sscanf (row[2],"%lf",&(Stats->TotalScore)) != 1)
-         Lay_ShowErrorAndExit ("Error when getting total score in test questions.");
+         Err_ShowErrorAndExit ("Error when getting total score in test questions.");
       Str_SetDecimalPointToLocal ();	// Return to local system
      }
    else
diff --git a/swad_test_import.c b/swad_test_import.c
index 3e40efa6..327fb0dd 100644
--- a/swad_test_import.c
+++ b/swad_test_import.c
@@ -32,6 +32,7 @@
 
 #include "swad_box.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_HTML.h"
@@ -202,7 +203,7 @@ void TsI_CreateXML (unsigned NumQsts,MYSQL_RES *mysql_res)
              Gbl.FileBrowser.TmpPubDir.L,
              Gbl.FileBrowser.TmpPubDir.R);
    if ((FileXML = fopen (PathPubFile,"wb")) == NULL)
-      Lay_ShowErrorAndExit ("Can not open target file.");
+      Err_ShowErrorAndExit ("Can not open target file.");
 
    /***** Start XML file *****/
    XML_WriteStartFile (FileXML,"test",false);
@@ -219,7 +220,7 @@ void TsI_CreateXML (unsigned NumQsts,MYSQL_RES *mysql_res)
       /* Get question code (row[0]) */
       row = mysql_fetch_row (mysql_res);
       if ((Question.QstCod = Str_ConvertStrCodToLongCod (row[0])) <= 0)
-         Lay_WrongQuestionExit ();
+         Err_WrongQuestionExit ();
 
       TsI_ExportQuestion (&Question,FileXML);
 
@@ -445,7 +446,7 @@ static void TsI_ReadQuestionsFromXMLFileAndStoreInDB (const char *FileNameXML)
 
    /***** Open file *****/
    if ((FileXML = fopen (FileNameXML,"rb")) == NULL)
-      Lay_ShowErrorAndExit ("Can not open XML file.");
+      Err_ShowErrorAndExit ("Can not open XML file.");
 
    /***** Compute file size *****/
    fseek (FileXML,0L,SEEK_END);
@@ -454,7 +455,7 @@ static void TsI_ReadQuestionsFromXMLFileAndStoreInDB (const char *FileNameXML)
 
    /***** Allocate memory for XML buffer *****/
    if ((XMLBuffer = malloc (FileSize + 1)) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    else
      {
       /***** Read file contents into XML buffer *****/
@@ -646,12 +647,12 @@ static void TsI_ImportQuestionsFromXMLBuffer (const char *XMLBuffer)
 		     Question.QstCod = -1L;
 		     Tst_InsertOrUpdateQstTagsAnsIntoDB (&Question);
 		     if (Question.QstCod <= 0)
-			Lay_ShowErrorAndExit ("Can not create question.");
+			Err_ShowErrorAndExit ("Can not create question.");
 		    }
 		 }
 	      }
 	    else	// Answer type not found
-	       Lay_WrongAnswerExit ();
+	       Err_WrongAnswerExit ();
 
 	    /***** Destroy test question *****/
 	    Tst_QstDestructor (&Question);
@@ -687,7 +688,7 @@ static Tst_AnswerType_t TsI_ConvertFromStrAnsTypXMLToAnsTyp (const char *StrAnsT
          if (!strcasecmp (StrAnsTypeXML,Tst_StrAnswerTypesXML[AnsType]))
             return AnsType;
 
-   Lay_WrongAnswerExit ();
+   Err_WrongAnswerExit ();
    return (Tst_AnswerType_t) 0;	// Not reached
   }
 
@@ -1001,7 +1002,7 @@ static void TsI_WriteRowImportedQst (struct XMLElement *StemElem,
             AnswerTextLength = strlen (Question->Answer.Options[NumOpt].Text) *
         	               Str_MAX_BYTES_PER_CHAR;
             if ((AnswerText = malloc (AnswerTextLength + 1)) == NULL)
-               Lay_NotEnoughMemoryExit ();
+               Err_NotEnoughMemoryExit ();
             Str_Copy (AnswerText,Question->Answer.Options[NumOpt].Text,
                       AnswerTextLength);
             Str_ChangeFormat (Str_FROM_HTML,Str_TO_RIGOROUS_HTML,
@@ -1016,7 +1017,7 @@ static void TsI_WriteRowImportedQst (struct XMLElement *StemElem,
 	          AnswerFeedbackLength = strlen (Question->Answer.Options[NumOpt].Feedback) *
 					 Str_MAX_BYTES_PER_CHAR;
 	          if ((AnswerFeedback = malloc (AnswerFeedbackLength + 1)) == NULL)
-		     Lay_NotEnoughMemoryExit ();
+		     Err_NotEnoughMemoryExit ();
 		  Str_Copy (AnswerFeedback,
 		            Question->Answer.Options[NumOpt].Feedback,
 		            AnswerFeedbackLength);
diff --git a/swad_test_print.c b/swad_test_print.c
index b3868981..133fbbe8 100644
--- a/swad_test_print.c
+++ b/swad_test_print.c
@@ -34,6 +34,7 @@
 
 #include "swad_action.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_HTML.h"
@@ -309,7 +310,7 @@ void TstPrn_ShowTestPrintToFillIt (struct TstPrn_Print *Print,
 
 	 /* Show question */
 	 if (!Tst_GetQstDataFromDB (&Question))	// Question exists
-	    Lay_WrongQuestionExit ();
+	    Err_WrongQuestionExit ();
 
 	 /* Write question and answers */
 	 TstPrn_WriteQstAndAnsToFill (&Print->PrintedQuestions[NumQst],NumQst,&Question);
@@ -890,7 +891,7 @@ static void TstPrn_GetCorrectIntAnswerFromDB (struct Tst_Question *Question)
    /***** Get correct answer *****/
    row = mysql_fetch_row (mysql_res);
    if (sscanf (row[0],"%ld",&Question->Answer.Integer) != 1)
-      Lay_WrongAnswerExit ();
+      Err_WrongAnswerExit ();
 
    /***** Free structure that stores the query result *****/
    DB_FreeMySQLResult (&mysql_res);
@@ -913,7 +914,7 @@ static void TstPrn_GetCorrectFltAnswerFromDB (struct Tst_Question *Question)
 
    /***** Check if number of rows is correct *****/
    if (Question->Answer.NumOptions != 2)
-      Lay_WrongAnswerExit ();
+      Err_WrongAnswerExit ();
 
    /***** Get float range *****/
    for (NumOpt = 0;
@@ -1257,10 +1258,10 @@ void TstPrn_GetIndexesFromStr (const char StrIndexesOneQst[Tst_MAX_BYTES_INDEXES
       Par_GetNextStrUntilComma (&Ptr,StrOneIndex,Cns_MAX_DECIMAL_DIGITS_UINT);
 
       if (sscanf (StrOneIndex,"%u",&(Indexes[NumOpt])) != 1)
-	 Lay_WrongAnswerIndexExit ();
+	 Err_WrongAnswerIndexExit ();
 
       if (Indexes[NumOpt] >= Tst_MAX_OPTIONS_PER_QUESTION)
-	 Lay_WrongAnswerIndexExit ();
+	 Err_WrongAnswerIndexExit ();
      }
 
    /***** Initialize remaining to 0 *****/
@@ -1296,10 +1297,10 @@ void TstPrn_GetAnswersFromStr (const char StrAnswersOneQst[Tst_MAX_BYTES_ANSWERS
       Par_GetNextStrUntilComma (&Ptr,StrOneAnswer,Cns_MAX_DECIMAL_DIGITS_UINT);
 
       if (sscanf (StrOneAnswer,"%u",&AnsUsr) != 1)
-	 Lay_WrongAnswerExit ();
+	 Err_WrongAnswerExit ();
 
       if (AnsUsr >= Tst_MAX_OPTIONS_PER_QUESTION)
-	 Lay_WrongAnswerExit ();
+	 Err_WrongAnswerExit ();
 
       UsrAnswers[AnsUsr] = true;
      }
@@ -1454,7 +1455,7 @@ static void TstPrn_WriteFltAnsPrint (struct UsrData *UsrDat,
 
    /***** Check if number of rows is correct *****/
    if (Question->Answer.NumOptions != 2)
-      Lay_WrongAnswerExit ();
+      Err_WrongAnswerExit ();
 
    /***** Header with the title of each column *****/
    HTM_TABLE_BeginPadding (2);
@@ -2104,7 +2105,7 @@ static void TstPrn_ShowUsrPrints (struct UsrData *UsrDat)
 
          /* Get print code (row[0]) */
 	 if ((Print.PrnCod = Str_ConvertStrCodToLongCod (row[0])) < 0)
-	    Lay_WrongTestExit ();
+	    Err_WrongTestExit ();
 
 	 /* Get print data */
          TstPrn_GetPrintDataByPrnCod (&Print);
@@ -2124,7 +2125,7 @@ static void TstPrn_ShowUsrPrints (struct UsrData *UsrDat)
 	      StartEndTime++)
 	   {
 	    if (asprintf (&Id,"tst_date_%u_%u",(unsigned) StartEndTime,UniqueId) < 0)
-	       Lay_NotEnoughMemoryExit ();
+	       Err_NotEnoughMemoryExit ();
 	    HTM_TD_Begin ("id=\"%s\" class=\"%s LT COLOR%u\"",
 		          Id,ClassDat,Gbl.RowEvenOdd);
 	    Dat_WriteLocalDateHMSFromUTC (Id,Print.TimeUTC[StartEndTime],
@@ -2399,7 +2400,7 @@ void TstPrn_ShowOnePrint (void)
    /***** Get the code of the test *****/
    TstPrn_ResetPrint (&Print);
    if ((Print.PrnCod = TstPrn_GetParamPrnCod ()) <= 0)
-      Lay_WrongTestExit ();
+      Err_WrongTestExit ();
 
    /***** Get test exam data *****/
    TstPrn_GetPrintDataByPrnCod (&Print);
@@ -2431,9 +2432,9 @@ void TstPrn_ShowOnePrint (void)
       if (!Usr_ChkUsrCodAndGetAllUsrDataFromUsrCod (&Gbl.Usrs.Other.UsrDat,
                                                     Usr_DONT_GET_PREFS,
                                                     Usr_DONT_GET_ROLE_IN_CURRENT_CRS))
-         Lay_WrongUserExit ();
+         Err_WrongUserExit ();
       if (!Usr_CheckIfICanViewTstExaMchResult (&Gbl.Usrs.Other.UsrDat))
-         Lay_NoPermissionExit ();
+         Err_NoPermissionExit ();
 
       /* User */
       HTM_TR_Begin (NULL);
@@ -2461,7 +2462,7 @@ void TstPrn_ShowOnePrint (void)
 	   StartEndTime++)
 	{
 	 if (asprintf (&Id,"tst_date_%u",(unsigned) StartEndTime) < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 HTM_TR_Begin (NULL);
 
@@ -2573,7 +2574,7 @@ void TstPrn_ShowOnePrint (void)
       Box_BoxEnd ();
      }
    else	// I am not allowed to view this test exam
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
   }
 
 /*****************************************************************************/
@@ -2782,12 +2783,12 @@ void TstPrn_GetPrintQuestionsFromDB (struct TstPrn_Print *Print)
 
 	 /* Get question code (row[0]) */
 	 if ((Print->PrintedQuestions[NumQst].QstCod = Str_ConvertStrCodToLongCod (row[0])) < 0)
-	    Lay_WrongQuestionExit ();
+	    Err_WrongQuestionExit ();
 
 	 /* Get score (row[1]) */
 	 Str_SetDecimalPointToUS ();	// To get the decimal point as a dot
          if (sscanf (row[1],"%lf",&Print->PrintedQuestions[NumQst].Score) != 1)
-            Lay_ShowErrorAndExit ("Wrong question score.");
+            Err_ShowErrorAndExit ("Wrong question score.");
          Str_SetDecimalPointToLocal ();	// Return to local system
 
 	 /* Get indexes for this question (row[2]) */
@@ -2803,7 +2804,7 @@ void TstPrn_GetPrintQuestionsFromDB (struct TstPrn_Print *Print)
    DB_FreeMySQLResult (&mysql_res);
 
    if (NumQsts != Print->NumQsts.All)
-      Lay_WrongExamExit ();
+      Err_WrongExamExit ();
   }
 
 /*****************************************************************************/
diff --git a/swad_test_visibility.c b/swad_test_visibility.c
index 38b383d8..1eb4e291 100644
--- a/swad_test_visibility.c
+++ b/swad_test_visibility.c
@@ -29,6 +29,7 @@
 #include <stdio.h>		// For asprintf
 #include <stdlib.h>		// For malloc, free
 
+#include "swad_error.h"
 #include "swad_HTML.h"
 #include "swad_parameter.h"
 #include "swad_test_visibility.h"
@@ -94,7 +95,7 @@ void TstVis_ShowVisibilityIcons (unsigned SelectedVisibility,bool Hidden)
       if (asprintf (&Title,"%s: %s",
 		    Txt_TST_STR_VISIBILITY[Visibility],
 		    Txt_TST_HIDDEN_VISIBLE[ItemVisible]) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       if (ItemVisible && !Hidden)
 	 Ico_PutIconOn  (Icons[Visibility][ItemVisible],Title);
       else
@@ -162,7 +163,7 @@ unsigned TstVis_GetVisibilityFromForm (void)
    /***** Allocate memory for list of attendance events selected *****/
    MaxSizeListVisibilitySelected = TstVis_NUM_ITEMS_VISIBILITY * (Cns_MAX_DECIMAL_DIGITS_UINT + 1);
    if ((StrVisibilitySelected = malloc (MaxSizeListVisibilitySelected + 1)) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Get parameter multiple with list of visibility items selected *****/
    Par_GetParMultiToText ("Visibility",StrVisibilitySelected,MaxSizeListVisibilitySelected);
diff --git a/swad_timeline_comment.c b/swad_timeline_comment.c
index 5af5591f..b29b5eb4 100644
--- a/swad_timeline_comment.c
+++ b/swad_timeline_comment.c
@@ -30,6 +30,7 @@
 #include <stdio.h>		// For asprintf
 #include <stdlib.h>		// For free
 
+#include "swad_error.h"
 #include "swad_forum.h"
 #include "swad_global.h"
 #include "swad_message.h"
@@ -496,7 +497,7 @@ static void Tml_Com_PutIconToToggleComms (const char *UniqueId,
 
    /***** Build onclick text *****/
    if (asprintf (&OnClick,"toggleComments('%s')",UniqueId) < 0)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Link to toggle on/off some divs *****/
    HTM_BUTTON_BUTTON_Begin (Text,The_ClassFormLinkInBox[Gbl.Prefs.Theme],OnClick);
diff --git a/swad_timeline_database.c b/swad_timeline_database.c
index b01101bf..2a731a8d 100644
--- a/swad_timeline_database.c
+++ b/swad_timeline_database.c
@@ -26,6 +26,7 @@
 /*****************************************************************************/
 
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_follow.h"
 #include "swad_global.h"
 #include "swad_timeline.h"
@@ -743,7 +744,7 @@ void Tml_DB_CreateSubQueryPublishers (const struct Tml_Timeline *Timeline,
 	       SubQueries->Publishers[0] = '\0';
 	       break;
 	    default:
-	       Lay_WrongWhoExit ();
+	       Err_WrongWhoExit ();
 	       break;
 	   }
 	 break;
diff --git a/swad_timeline_form.c b/swad_timeline_form.c
index 3a2b661a..a8928d7a 100644
--- a/swad_timeline_form.c
+++ b/swad_timeline_form.c
@@ -31,6 +31,7 @@
 #include <stdlib.h>		// For free
 
 #include "swad_action.h"
+#include "swad_error.h"
 #include "swad_global.h"
 #include "swad_timeline.h"
 #include "swad_timeline_favourite.h"
@@ -271,7 +272,7 @@ void Tml_Frm_FormFavSha (const struct TL_Form *Form)
 		    Gbl.Session.Id,
 		    ParamStr,
 		    Gbl.Usrs.Other.UsrDat.EnUsrCod) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       Frm_BeginFormUniqueAnchorOnSubmit (ActUnk,"timeline",OnSubmit);
      }
    else
@@ -282,7 +283,7 @@ void Tml_Frm_FormFavSha (const struct TL_Form *Form)
 		    Act_GetActCod (Tml_Frm_ActionGbl[Form->Action]),
 		    Gbl.Session.Id,
 		    ParamStr) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
       Frm_BeginFormUniqueAnchorOnSubmit (ActUnk,NULL,OnSubmit);
      }
    Ico_PutIconLink (Form->Icon,Form->Title);
@@ -326,7 +327,7 @@ void Tml_Frm_FormToShowHiddenComms (long NotCod,
 			  IdComms,
 			  NumInitialComms,
 			  Gbl.Usrs.Other.UsrDat.EnUsrCod) < 0)
-	       Lay_NotEnoughMemoryExit ();
+	       Err_NotEnoughMemoryExit ();
 	    Frm_BeginFormUniqueAnchorOnSubmit (ActUnk,"timeline",OnSubmit);
 	   }
 	 else
@@ -341,7 +342,7 @@ void Tml_Frm_FormToShowHiddenComms (long NotCod,
 			  NotCod,
 			  IdComms,
 			  NumInitialComms) < 0)
-	       Lay_NotEnoughMemoryExit ();
+	       Err_NotEnoughMemoryExit ();
 	    Frm_BeginFormUniqueAnchorOnSubmit (ActUnk,NULL,OnSubmit);
 	   }
 
diff --git a/swad_timeline_publication.c b/swad_timeline_publication.c
index 6bc1d25a..30bf0c2c 100644
--- a/swad_timeline_publication.c
+++ b/swad_timeline_publication.c
@@ -28,6 +28,7 @@
 #include <stdlib.h>		// For malloc and free
 #include <string.h>		// For string functions
 
+#include "swad_error.h"
 #include "swad_follow.h"
 #include "swad_global.h"
 #include "swad_profile.h"
@@ -329,7 +330,7 @@ static struct Tml_Pub_Publication *Tml_Pub_SelectTheMostRecentPub (const struct
      {
       /* Allocate space for publication */
       if ((Pub = malloc (sizeof (*Pub))) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
 
       /* Get data of publication */
       Tml_Pub_GetDataOfPubFromNextRow (mysql_res,Pub);
diff --git a/swad_timeline_user.c b/swad_timeline_user.c
index 9352fb29..32d42bb8 100644
--- a/swad_timeline_user.c
+++ b/swad_timeline_user.c
@@ -30,6 +30,7 @@
 #include <linux/limits.h>	// For PATH_MAX
 #include <stdio.h>		// For asprintf
 
+#include "swad_error.h"
 #include "swad_global.h"
 #include "swad_photo.h"
 #include "swad_timeline.h"
@@ -246,7 +247,7 @@ bool Tml_Usr_CheckIfFavedSharedByUsr (Tml_Usr_FavSha_t FavSha,long Cod,long UsrC
       case Tml_Usr_SHA_UNS_NOTE:
 	 return Tml_DB_CheckIfSharedByUsr (Cod,UsrCod);
       default:
-         Lay_ShowErrorAndExit ("Wrong fav/share action.");
+         Err_ShowErrorAndExit ("Wrong fav/share action.");
      }
 
    return false;	// Not reached
@@ -268,7 +269,7 @@ static unsigned Tml_Usr_GetListFaversOrSharers (Tml_Usr_FavSha_t FavSha,
       case Tml_Usr_SHA_UNS_NOTE:
 	 return Tml_DB_GetSharers (Cod,UsrCod,MaxUsrs,mysql_res);
       default:
-         Lay_ShowErrorAndExit ("Wrong fav/share action.");
+         Err_ShowErrorAndExit ("Wrong fav/share action.");
      }
 
    return 0;	// Not reached
@@ -359,7 +360,7 @@ bool Tml_Usr_CheckIfICanFavSha (long Cod,long UsrCod)
 			   I can not fav/share my own notes/comments *****/
    if (!Gbl.Usrs.Me.Logged || Usr_ItsMe (UsrCod))
      {
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
       return false;	// Not reached
      }
 
@@ -385,7 +386,7 @@ bool Tml_Usr_CheckIfICanRemove (long Cod,long UsrCod)
 			   I can only remove my own notes/comments *****/
    if (!Gbl.Usrs.Me.Logged || !Usr_ItsMe (UsrCod))
      {
-      Lay_NoPermissionExit ();
+      Err_NoPermissionExit ();
       return false;	// Not reached
      }
 
diff --git a/swad_timetable.c b/swad_timetable.c
index 0d613e13..dd9231d0 100644
--- a/swad_timetable.c
+++ b/swad_timetable.c
@@ -34,6 +34,7 @@
 #include "swad_box.h"
 #include "swad_calendar.h"
 #include "swad_database.h"
+#include "swad_error.h"
 #include "swad_form.h"
 #include "swad_global.h"
 #include "swad_HTML.h"
@@ -188,7 +189,7 @@ static void Tmt_TimeTableConfigureIntervalsAndAllocateTimeTable (struct Tmt_Time
 	   Weekday++)
 	 if ((Tmt_TimeTable[Weekday] = malloc (Timetable->Config.IntervalsPerDay *
 					      sizeof (*Tmt_TimeTable[Weekday]))) == NULL)
-            Lay_NotEnoughMemoryExit ();
+            Err_NotEnoughMemoryExit ();
      }
    else
      {
@@ -288,12 +289,12 @@ static void Tmt_GetParamsTimeTable (struct Tmt_Timetable *Timetable)
       if (!strcmp (StrClassType,Tmt_ClassTypeDB[Timetable->ClassType]))
          break;
    if (Timetable->ClassType > (Tmt_ClassType_t) (Tmt_NUM_CLASS_TYPES - 1))
-      Lay_ShowErrorAndExit ("Type of timetable cell is missing.");
+      Err_ShowErrorAndExit ("Type of timetable cell is missing.");
 
    /***** Get class duration *****/
    Par_GetParToText ("TTDur",StrDuration,Tmt_MAX_BYTES_STR_DURATION);
    if (sscanf (StrDuration,"%u:%u",&Hours,&Minutes) != 2)
-      Lay_ShowErrorAndExit ("Duration is missing.");
+      Err_ShowErrorAndExit ("Duration is missing.");
    Timetable->DurationIntervals = Hours * Timetable->Config.IntervalsPerHour +
 	                          Minutes / Timetable->Config.Range.MinutesPerInterval;
 
@@ -344,7 +345,7 @@ void Tmt_ShowClassTimeTable (void)
          Timetable.Type = Tmt_MY_TIMETABLE;
          break;
       default:
-	 Lay_WrongActionExit ();
+	 Err_WrongActionExit ();
      }
 
    Timetable.ContextualIcons.PutIconEditCrsTT = (Timetable.Type == Tmt_COURSE_TIMETABLE &&
@@ -892,11 +893,11 @@ static void Tmt_FillTimeTableFromDB (struct Tmt_Timetable *Timetable,
 
 	 /* StartTime formatted as seconds (row[1]) */
 	 if (sscanf (row[1],"%u",&StartTimeSeconds) != 1)
-	    Lay_ShowErrorAndExit ("Wrong start time in timetable.");
+	    Err_ShowErrorAndExit ("Wrong start time in timetable.");
 
 	 /* Duration formatted as seconds (row[2]) */
 	 if (sscanf (row[2],"%u",&DurationSeconds) != 1)
-	    Lay_ShowErrorAndExit ("Wrong duration in timetable.");
+	    Err_ShowErrorAndExit ("Wrong duration in timetable.");
 	 EndTimeSeconds = StartTimeSeconds + DurationSeconds;
 
 	 /* Compute hours and resolution */
@@ -949,24 +950,24 @@ static void Tmt_FillTimeTableFromDB (struct Tmt_Timetable *Timetable,
 
 	 /* Day of week (row[0]) */
 	 if (sscanf (row[0],"%u",&Weekday) != 1)
-	    Lay_ShowErrorAndExit ("Wrong day of week in timetable.");
+	    Err_ShowErrorAndExit ("Wrong day of week in timetable.");
 	 if (Weekday >= Tmt_DAYS_PER_WEEK)
-	    Lay_ShowErrorAndExit ("Wrong day of week in timetable.");
+	    Err_ShowErrorAndExit ("Wrong day of week in timetable.");
 
 	 /* StartTime formatted as seconds (row[1])
 	    --> StartTime in number of intervals */
 	 if (sscanf (row[1],"%u",&StartTimeSeconds) != 1)
-	    Lay_ShowErrorAndExit ("Wrong start time in timetable.");
+	    Err_ShowErrorAndExit ("Wrong start time in timetable.");
 	 Interval = StartTimeSeconds /
 	            Timetable->Config.SecondsPerInterval;
 	 if (Interval < Timetable->Config.IntervalsBeforeStartHour)
-	    Lay_ShowErrorAndExit ("Wrong start time in timetable.");
+	    Err_ShowErrorAndExit ("Wrong start time in timetable.");
 	 Interval -= Timetable->Config.IntervalsBeforeStartHour;
 
 	 /* Duration formatted as seconds (row[2])
 	    --> Duration in number of intervals */
 	 if (sscanf (row[2],"%u",&DurationSeconds) != 1)
-	    Lay_ShowErrorAndExit ("Wrong duration in timetable.");
+	    Err_ShowErrorAndExit ("Wrong duration in timetable.");
 	 DurationNumIntervals = DurationSeconds /
 	                        Timetable->Config.SecondsPerInterval;
 
@@ -984,7 +985,7 @@ static void Tmt_FillTimeTableFromDB (struct Tmt_Timetable *Timetable,
 		     break;
 		    }
 	       if (!Found)
-		  Lay_ShowErrorAndExit ("Wrong type of class in timetable.");
+		  Err_ShowErrorAndExit ("Wrong type of class in timetable.");
 	       break;
 	    case Tmt_TUTORING_TIMETABLE:
 	       ClassType = Tmt_TUTORING;
@@ -1426,7 +1427,7 @@ static unsigned Tmt_CalculateColsToDrawInCell (const struct Tmt_Timetable *Timet
               and initialize to false by using calloc *****/
       if ((Tmt_IntervalsChecked = calloc (Timetable->Config.IntervalsPerDay,
                                          sizeof (*Tmt_IntervalsChecked))) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
 
    ColumnsToDraw = Tmt_TimeTable[Weekday][Interval].NumColumns;
 
@@ -1567,32 +1568,32 @@ static void Tmt_TimeTableDrawCell (const struct Tmt_Timetable *Timetable,
    if (RowSpan > 1)
      {
       if (asprintf (&RowSpanStr,"rowspan=\"%u\" ",RowSpan) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
      }
    else
      {
       if (asprintf (&RowSpanStr,"%s","") < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
      }
    if (ColSpan > 1)
      {
       if (asprintf (&ColSpanStr,"colspan=\"%u\" ",ColSpan) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
      }
    else
      {
       if (asprintf (&ColSpanStr,"%s","") < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
      }
    if (ClassType == Tmt_FREE)
      {
       if (asprintf (&ClassStr,"%s%u",TimeTableClasses[ClassType],Interval % 4) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
      }
    else
      {
       if (asprintf (&ClassStr,"%s CM DAT_SMALL",TimeTableClasses[ClassType]) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
      }
 
    /* Begin cell */
@@ -1672,7 +1673,7 @@ static void Tmt_TimeTableDrawCell (const struct Tmt_Timetable *Timetable,
 	 /***** Create unique string for this cell used in labels *****/
 	 if (asprintf (&CellStr,"%02u%02u%02u",
 		       Weekday,Interval,Column) < 0)
-	    Lay_NotEnoughMemoryExit ();
+	    Err_NotEnoughMemoryExit ();
 
 	 /***** Put hidden parameters *****/
          Par_PutHiddenParamUnsigned (NULL,"TTDay",Weekday);
@@ -1707,7 +1708,7 @@ static void Tmt_TimeTableDrawCell (const struct Tmt_Timetable *Timetable,
 		          (Dur / Timetable->Config.IntervalsPerHour),		// Hours
 		          (Dur % Timetable->Config.IntervalsPerHour) *
 		          Timetable->Config.Range.MinutesPerInterval) < 0)	// Minutes
-	       Lay_NotEnoughMemoryExit ();
+	       Err_NotEnoughMemoryExit ();
 	    Par_PutHiddenParamString (NULL,"TTDur",TTDur);
 	    free (TTDur);
 	   }
@@ -1732,7 +1733,7 @@ static void Tmt_TimeTableDrawCell (const struct Tmt_Timetable *Timetable,
 			     (Dur / Timetable->Config.IntervalsPerHour),	// Hours
 			     (Dur % Timetable->Config.IntervalsPerHour) *
 			     Timetable->Config.Range.MinutesPerInterval) < 0)	// Minutes
-		  Lay_NotEnoughMemoryExit ();
+		  Err_NotEnoughMemoryExit ();
 	       HTM_OPTION (HTM_Type_STRING,TTDur,
 			   Dur == DurationNumIntervals,false,
 			   "%s",TTDur);
@@ -1767,12 +1768,12 @@ static void Tmt_TimeTableDrawCell (const struct Tmt_Timetable *Timetable,
 		     if (Grp->Room.RooCod > 0)
 		       {
 			if (asprintf (&Room," (%s)",Grp->Room.ShrtName) < 0)
-			   Lay_NotEnoughMemoryExit ();
+			   Err_NotEnoughMemoryExit ();
 		       }
 		     else
 		       {
 			if (asprintf (&Room,"%s","") < 0)
-			   Lay_NotEnoughMemoryExit ();
+			   Err_NotEnoughMemoryExit ();
 		       }
 		     HTM_OPTION (HTM_Type_LONG,&Grp->GrpCod,
 				 GrpCod == Grp->GrpCod,false,
diff --git a/swad_user.c b/swad_user.c
index f563c0f9..54271b42 100644
--- a/swad_user.c
+++ b/swad_user.c
@@ -48,6 +48,7 @@
 #include "swad_department.h"
 #include "swad_duplicate.h"
 #include "swad_enrolment.h"
+#include "swad_error.h"
 #include "swad_figure.h"
 #include "swad_figure_cache.h"
 #include "swad_follow.h"
@@ -305,7 +306,7 @@ void Usr_UsrDataConstructor (struct UsrData *UsrDat)
   {
    /***** Allocate memory for the comments *****/
    if ((UsrDat->Comments = malloc (Cns_MAX_BYTES_TEXT + 1)) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Initialize to zero the data of the user *****/
    Usr_ResetUsrDataExceptUsrCodAndIDs (UsrDat);
@@ -422,7 +423,7 @@ void Usr_AllocateListUsrCods (struct ListUsrCods *ListUsrCods)
   {
    if ((ListUsrCods->Lst = malloc (ListUsrCods->NumUsrs *
                                    sizeof (*ListUsrCods->Lst))) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
   }
 
 /*****************************************************************************/
@@ -467,7 +468,7 @@ void Usr_GetUsrCodFromEncryptedUsrCod (struct UsrData *UsrDat)
 			   " FROM usr_data"
 			  " WHERE EncryptedUsrCod='%s'",
 			  UsrDat->EnUsrCod) != 1)
-         Lay_ShowErrorAndExit ("Error when getting user's code.");
+         Err_ShowErrorAndExit ("Error when getting user's code.");
 
       /***** Get user's code *****/
       row = mysql_fetch_row (mysql_res);
@@ -579,7 +580,7 @@ void Usr_GetUsrDataFromUsrCod (struct UsrData *UsrDat,
      }
 
    if (NumRows != 1)
-      Lay_WrongUserExit ();
+      Err_WrongUserExit ();
 
    /***** Read user's data *****/
    row = mysql_fetch_row (mysql_res);
@@ -837,7 +838,7 @@ static void Usr_GetMyLastData (void)
       DB_FreeMySQLResult (&mysql_res);
      }
    else
-      Lay_ShowErrorAndExit ("Error when getting user's last data.");
+      Err_ShowErrorAndExit ("Error when getting user's last data.");
   }
 
 /*****************************************************************************/
@@ -1145,7 +1146,7 @@ unsigned Usr_GetNumUsrsInCrssOfAUsr (long UsrCod,Rol_Role_t UsrRole,
 	 break;
       default:
 	 SubQueryRole[0] = '\0';
-	 Lay_WrongRoleExit ();
+	 Err_WrongRoleExit ();
 	 break;
      }
    DB_Query ("can not create temporary table",
@@ -1574,7 +1575,7 @@ void Usr_GetMyCountrs (void)
 	 if ((CtyCod = Str_ConvertStrCodToLongCod (row[0])) > 0)
 	   {
 	    if (Gbl.Usrs.Me.MyCtys.Num == Cty_MAX_COUNTRS_PER_USR)
-	       Lay_ShowErrorAndExit ("Maximum number of countries of a user exceeded.");
+	       Err_ShowErrorAndExit ("Maximum number of countries of a user exceeded.");
 
 	    Gbl.Usrs.Me.MyCtys.Ctys[Gbl.Usrs.Me.MyCtys.Num].CtyCod  = CtyCod;
 	    Gbl.Usrs.Me.MyCtys.Ctys[Gbl.Usrs.Me.MyCtys.Num].MaxRole = Rol_ConvertUnsignedStrToRole (row[1]);
@@ -1621,7 +1622,7 @@ void Usr_GetMyInstits (void)
 	 if ((InsCod = Str_ConvertStrCodToLongCod (row[0])) > 0)
 	   {
 	    if (Gbl.Usrs.Me.MyInss.Num == Ins_MAX_INSTITS_PER_USR)
-	       Lay_ShowErrorAndExit ("Maximum number of institutions of a user exceeded.");
+	       Err_ShowErrorAndExit ("Maximum number of institutions of a user exceeded.");
 
 	    Gbl.Usrs.Me.MyInss.Inss[Gbl.Usrs.Me.MyInss.Num].InsCod  = InsCod;
 	    Gbl.Usrs.Me.MyInss.Inss[Gbl.Usrs.Me.MyInss.Num].MaxRole = Rol_ConvertUnsignedStrToRole (row[1]);
@@ -1668,7 +1669,7 @@ void Usr_GetMyCenters (void)
 	 if ((CtrCod = Str_ConvertStrCodToLongCod (row[0])) > 0)
 	   {
 	    if (Gbl.Usrs.Me.MyCtrs.Num == Ctr_MAX_CENTERS_PER_USR)
-	       Lay_ShowErrorAndExit ("Maximum number of centers of a user exceeded.");
+	       Err_ShowErrorAndExit ("Maximum number of centers of a user exceeded.");
 
 	    Gbl.Usrs.Me.MyCtrs.Ctrs[Gbl.Usrs.Me.MyCtrs.Num].CtrCod = CtrCod;
 	    Gbl.Usrs.Me.MyCtrs.Ctrs[Gbl.Usrs.Me.MyCtrs.Num].MaxRole = Rol_ConvertUnsignedStrToRole (row[1]);
@@ -1715,7 +1716,7 @@ void Usr_GetMyDegrees (void)
 	 if ((DegCod = Str_ConvertStrCodToLongCod (row[0])) > 0)
 	   {
 	    if (Gbl.Usrs.Me.MyDegs.Num == Deg_MAX_DEGREES_PER_USR)
-	       Lay_ShowErrorAndExit ("Maximum number of degrees of a user exceeded.");
+	       Err_ShowErrorAndExit ("Maximum number of degrees of a user exceeded.");
 
 	    Gbl.Usrs.Me.MyDegs.Degs[Gbl.Usrs.Me.MyDegs.Num].DegCod  = DegCod;
 	    Gbl.Usrs.Me.MyDegs.Degs[Gbl.Usrs.Me.MyDegs.Num].MaxRole = Rol_ConvertUnsignedStrToRole (row[1]);
@@ -1794,7 +1795,7 @@ void Usr_GetMyCourses (void)
       if (CrsCod > 0)
 	{
 	 if (Gbl.Usrs.Me.MyCrss.Num == Crs_MAX_COURSES_PER_USR)
-	    Lay_ShowErrorAndExit ("Maximum number of courses of a user exceeded.");
+	    Err_ShowErrorAndExit ("Maximum number of courses of a user exceeded.");
 
 	 Gbl.Usrs.Me.MyCrss.Crss[Gbl.Usrs.Me.MyCrss.Num].CrsCod = CrsCod;
 	 Gbl.Usrs.Me.MyCrss.Crss[Gbl.Usrs.Me.MyCrss.Num].Role   = Rol_ConvertUnsignedStrToRole (row[1]);
@@ -2981,7 +2982,7 @@ void Usr_GetParamOtherUsrCodEncrypted (struct UsrData *UsrDat)
      {
       Usr_GetUsrCodFromEncryptedUsrCod (UsrDat);
       if (UsrDat->UsrCod <= 0)	// Check is user's code is valid
-         Lay_WrongUserExit ();
+         Err_WrongUserExit ();
      }
    else
       UsrDat->UsrCod = -1L;
@@ -3150,7 +3151,7 @@ void Usr_ChkUsrAndGetUsrData (void)
    if (FormLogin.PutForm)
      {
       Usr_WriteFormLogin (FormLogin.Action,FormLogin.FuncParams);
-      Lay_ShowErrorAndExit (NULL);
+      Err_ShowErrorAndExit (NULL);
      }
 
    /***** Adjust tab and action *****/
@@ -4473,7 +4474,7 @@ static void Usr_BuildQueryToGetUsrsLstCrs (char **Query,Rol_Role_t Role)
 
    /***** Allocate space for query *****/
    if ((*Query = malloc (Usr_MAX_BYTES_QUERY_GET_LIST_USRS + 1)) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Create query for users in the course *****/
    if (Gbl.Action.Act == ActReqMsgUsr)        // Selecting users to write a message
@@ -4513,7 +4514,7 @@ static void Usr_BuildQueryToGetUsrsLstCrs (char **Query,Rol_Role_t Role)
       /***** Allocate memory for list of booleans AddStdsWithoutGroupOf *****/
       if ((AddStdsWithoutGroupOf = calloc (Gbl.Crs.Grps.GrpTypes.Num,
                                            sizeof (*AddStdsWithoutGroupOf))) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
 
       /***** Initialize vector of booleans that indicates whether it's necessary add to the list
              the students who don't belong to any group of each type *****/
@@ -4760,7 +4761,7 @@ void Usr_GetListUsrs (Hie_Lvl_Level_t Scope,Rol_Role_t Role)
 	 Usr_BuildQueryToGetUsrsLstCrs (&Query,Role);
 	 break;
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 break;
      }
 /*
@@ -4922,7 +4923,7 @@ void Usr_SearchListUsrs (Rol_Role_t Role)
 			      OrderQuery);
 	       break;
 	    default:
-	       Lay_WrongScopeExit ();
+	       Err_WrongScopeExit ();
 	       break;
 	   }
          break;
@@ -5082,12 +5083,12 @@ void Usr_SearchListUsrs (Rol_Role_t Role)
 			      OrderQuery);
 	       break;
 	    default:
-	       Lay_WrongScopeExit ();
+	       Err_WrongScopeExit ();
 	       break;
 	   }
 	 break;
       default:
-	 Lay_WrongRoleExit ();
+	 Err_WrongRoleExit ();
 	 break;
      }
 
@@ -5348,7 +5349,7 @@ static void Usr_GetAdmsLst (Hie_Lvl_Level_t Scope)
 			Sco_GetDBStrFromScope (Hie_Lvl_DEG),Gbl.Hierarchy.Deg.DegCod);
          break;
       default:        // not aplicable
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
          break;
      }
 
@@ -5599,7 +5600,7 @@ static void Usr_GetListUsrsFromQuery (char *Query,Rol_Role_t Role,Hie_Lvl_Level_
 		  switch (Scope)
 		    {
 		     case Hie_Lvl_UNK:	// Unknown
-			Lay_WrongScopeExit ();
+			Err_WrongScopeExit ();
 			break;
 		     case Hie_Lvl_SYS:	// System
 			// Query result has not a column with the acceptation
@@ -5637,7 +5638,7 @@ static void Usr_GetListUsrsFromQuery (char *Query,Rol_Role_t Role,Hie_Lvl_Level_
 		  switch (Scope)
 		    {
 		     case Hie_Lvl_UNK:	// Unknown
-			Lay_WrongScopeExit ();
+			Err_WrongScopeExit ();
 			break;
 		     case Hie_Lvl_SYS:	// System
 		     case Hie_Lvl_CTY:	// Country
@@ -5656,7 +5657,7 @@ static void Usr_GetListUsrsFromQuery (char *Query,Rol_Role_t Role,Hie_Lvl_Level_
 		    }
         	  break;
                default:
-		  Lay_WrongRoleExit ();
+		  Err_WrongRoleExit ();
         	  break;
 	      }
 
@@ -5670,7 +5671,7 @@ static void Usr_GetListUsrsFromQuery (char *Query,Rol_Role_t Role,Hie_Lvl_Level_
    DB_FreeMySQLResult (&mysql_res);
 
    if (Abort)
-      Lay_ShowErrorAndExit (NULL);
+      Err_ShowErrorAndExit (NULL);
   }
 
 /*****************************************************************************/
@@ -5712,7 +5713,7 @@ if (Gbl.Usrs.Me.Roles.LoggedRole == Rol_SYS_ADM)
    if (Gbl.Usrs.LstUsrs[Role].NumUsrs)
       if ((Gbl.Usrs.LstUsrs[Role].Lst = calloc (Gbl.Usrs.LstUsrs[Role].NumUsrs,
                                                 sizeof (*Gbl.Usrs.LstUsrs[Role].Lst))) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
   }
 
 /*****************************************************************************/
@@ -5801,7 +5802,7 @@ void Usr_CreateListSelectedUsrsCodsAndFillWithOtherUsr (struct SelectedUsrs *Sel
      {
       if ((SelectedUsrs->List[Rol_UNK] =
 	   malloc (Cry_BYTES_ENCRYPTED_STR_SHA256_BASE64 + 1)) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
       Str_Copy (SelectedUsrs->List[Rol_UNK],Gbl.Usrs.Other.UsrDat.EnUsrCod,
 		Cry_BYTES_ENCRYPTED_STR_SHA256_BASE64);
       SelectedUsrs->Filled = true;
@@ -5917,12 +5918,12 @@ static void Usr_BuildParamName (char **ParamName,
    if (ParamSuffix)
      {
       if (asprintf (ParamName,"%s%s",ParamRoot,ParamSuffix) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
      }
    else
      {
       if (asprintf (ParamName,"%s",ParamRoot) < 0)
-	 Lay_NotEnoughMemoryExit ();
+	 Err_NotEnoughMemoryExit ();
      }
   }
 
@@ -6189,7 +6190,7 @@ static void Usr_AllocateListSelectedEncryptedUsrCods (struct SelectedUsrs *Selec
      {
       if ((SelectedUsrs->List[Role] =
 	   malloc (Usr_MAX_BYTES_LIST_ENCRYPTED_USR_CODS + 1)) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
       SelectedUsrs->List[Role][0] = '\0';
      }
   }
@@ -6237,7 +6238,7 @@ void Usr_GetListSelectedUsrCods (struct SelectedUsrs *SelectedUsrs,
    /***** Create list of user codes *****/
    if ((*LstSelectedUsrCods = calloc (NumUsrsInList,
                                       sizeof (**LstSelectedUsrCods))) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    /***** Initialize structure with user's data *****/
    Usr_UsrDataConstructor (&UsrDat);
@@ -6279,7 +6280,7 @@ void Usr_CreateSubqueryUsrCods (long LstSelectedUsrCods[],
    /***** Allocate space for subquery *****/
    MaxLength = NumUsrsInList * (1 + Cns_MAX_DECIMAL_DIGITS_LONG);
    if ((*SubQueryUsrs = malloc (MaxLength + 1)) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
    (*SubQueryUsrs)[0] = '\0';
 
    /***** Build subquery *****/
@@ -6311,7 +6312,7 @@ static void Usr_AllocateListOtherRecipients (void)
    if (!Gbl.Usrs.ListOtherRecipients)
      {
       if ((Gbl.Usrs.ListOtherRecipients = malloc (Nck_MAX_BYTES_LIST_NICKS + 1)) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
       Gbl.Usrs.ListOtherRecipients[0] = '\0';
      }
   }
@@ -6621,7 +6622,7 @@ static void Usr_PutCheckboxToSelectAllUsers (Rol_Role_t Role,
       free (ParamName);
      }
    else
-      Lay_WrongRoleExit ();
+      Err_WrongRoleExit ();
    Sex = Usr_GetSexOfUsrsLst (Role);
    HTM_TxtColon (Gbl.Usrs.LstUsrs[Role].NumUsrs == 1 ? Txt_ROLES_SINGUL_Abc[Role][Sex] :
                                                        Txt_ROLES_PLURAL_Abc[Role][Sex]);
@@ -6701,7 +6702,7 @@ static void Usr_PutCheckboxToSelectUser (Rol_Role_t Role,
       free (ParamName);
      }
    else
-      Lay_WrongRoleExit ();
+      Err_WrongRoleExit ();
   }
 
 /*****************************************************************************/
@@ -6845,7 +6846,7 @@ static void Usr_ListMainDataStds (bool PutCheckBoxToSelectUsr)
       /***** Allocate memory for the string with the list of group names where student belongs to *****/
       if ((GroupNames = malloc (Gbl.Crs.Grps.GrpTypes.NumGrpsTotal *
                                 (Grp_MAX_BYTES_GROUP_NAME + 3))) == NULL)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
 
       /***** Begin table with list of students *****/
       if (!Gbl.Usrs.ClassPhoto.AllGroups)
@@ -7157,7 +7158,7 @@ void Usr_ListAllDataStds (void)
 	{
 	 Length = (Grp_MAX_BYTES_GROUP_NAME + 2) * Gbl.Crs.Grps.GrpTypes.NumGrpsTotal;
          if ((GroupNames = malloc (Length + 1)) == NULL)
-            Lay_NotEnoughMemoryExit ();
+            Err_NotEnoughMemoryExit ();
 	}
 
       /***** Begin table with list of students *****/
@@ -7829,7 +7830,7 @@ static void Usr_GetMyUsrListTypeFromDB (void)
       Gbl.Usrs.Me.ListType = Usr_SHOW_USRS_TYPE_DEFAULT;
    else				// Error in database:
 				// more than one row for a user in course
-      Lay_ShowErrorAndExit ("Error when getting type of listing of users.");
+      Err_ShowErrorAndExit ("Error when getting type of listing of users.");
 
    /***** Free structure that stores the query result *****/
    DB_FreeMySQLResult (&mysql_res);
@@ -7929,7 +7930,7 @@ static void Usr_GetMyColsClassPhotoFromDB (void)
         }
       else if (NumRows > 1)	// Error in database:
 				// more than one row for a user in course
-         Lay_ShowErrorAndExit ("Error when getting number of columns"
+         Err_ShowErrorAndExit ("Error when getting number of columns"
 			       " in class photo.");
 
       /***** Free structure that stores the query result *****/
@@ -8036,7 +8037,7 @@ void Usr_GetMyPrefAboutListWithPhotosFromDB (void)
         }
       else if (NumRows > 1)        // Error in database:
 				   // more than one row for a user in course
-         Lay_ShowErrorAndExit ("Error when checking if listing of users"
+         Err_ShowErrorAndExit ("Error when checking if listing of users"
 			       " must show photos.");
 
       /***** Free structure that stores the query result *****/
@@ -9434,7 +9435,7 @@ unsigned Usr_GetTotalNumberOfUsers (void)
 	         (1 << Rol_TCH);
          return Usr_GetCachedNumUsrsInCrss (Gbl.Scope.Current,Cod,Roles);	// All users in courses
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 return 0;	// Not reached
      }
   }
@@ -9671,7 +9672,7 @@ unsigned Usr_GetNumUsrsInCrss (Hie_Lvl_Level_t Scope,long Cod,unsigned Roles)
 			   SubQueryRoles);
          break;
       default:
-	 Lay_WrongScopeExit ();
+	 Err_WrongScopeExit ();
 	 NumUsrs = 0;	// Not reached. Initialized to avoid warning.
 	 break;
      }
@@ -9712,7 +9713,7 @@ static FigCch_FigureCached_t Usr_GetFigureNumUsrsInCrss (unsigned Roles)
 	   1 << Rol_TCH:	// Any user in courses
 	 return FigCch_NUM_USRS_IN_CRSS;
       default:
-	 Lay_WrongRoleExit ();
+	 Err_WrongRoleExit ();
 	 return FigCch_UNKNOWN;	// Not reached
      }
   }
@@ -9888,7 +9889,7 @@ static double Usr_GetNumCrssPerUsr (Hie_Lvl_Level_t Scope,long Cod,Rol_Role_t Ro
       case Hie_Lvl_CRS:
          return 1.0;
       default:
-         Lay_WrongScopeExit ();
+         Err_WrongScopeExit ();
          return 0.0;	// Not reached
      }
   }
@@ -10064,7 +10065,7 @@ static double Usr_GetNumUsrsPerCrs (Hie_Lvl_Level_t Scope,long Cod,Rol_Role_t Ro
 							         1 << Role);
 
       default:
-         Lay_WrongScopeExit ();
+         Err_WrongScopeExit ();
          return 0.0;	// Not reached
      }
   }
@@ -10295,7 +10296,7 @@ void Usr_PutWhoIcon (Usr_Who_t Who)
 			  "ICO_HIGHLIGHT ICOx20");
 	 break;
       default:
-	Lay_WrongWhoExit ();
+	Err_WrongWhoExit ();
 	break;
      }
   }
diff --git a/swad_xml.c b/swad_xml.c
index 15300d5c..765b8645 100644
--- a/swad_xml.c
+++ b/swad_xml.c
@@ -31,6 +31,7 @@
 #include <string.h>		// For strlen (), etc.
 
 #include "swad_changelog.h"
+#include "swad_error.h"
 #include "swad_global.h"
 #include "swad_HTML.h"
 #include "swad_xml.h"
@@ -101,7 +102,7 @@ void XML_GetTree (const char *XMLBuffer,struct XMLElement **XMLRootElem)
   {
    /***** Allocate space for the root element *****/
    if ((*XMLRootElem = calloc (1,sizeof (**XMLRootElem))) == NULL)
-      Lay_NotEnoughMemoryExit ();
+      Err_NotEnoughMemoryExit ();
 
    Gbl.XMLPtr = XMLBuffer;
    XML_GetElement (*XMLRootElem);
@@ -156,14 +157,14 @@ static void XML_GetElement (struct XMLElement *ParentElem)
             snprintf (ErrorTxt,sizeof (ErrorTxt),
 	              "XML syntax error. Expect end tag &lt;/%s&gt;.",
 		      ParentElem->TagName);
-            Lay_ShowErrorAndExit (ErrorTxt);
+            Err_ShowErrorAndExit (ErrorTxt);
            }
          if (strncmp (ParentElem->TagName,Gbl.XMLPtr,EndTagNameLength))	// XML tags are case sensitive
            {
             snprintf (ErrorTxt,sizeof (ErrorTxt),
 	              "XML syntax error. Expect end tag &lt;/%s&gt;.",
 		      ParentElem->TagName);
-            Lay_ShowErrorAndExit (ErrorTxt);
+            Err_ShowErrorAndExit (ErrorTxt);
            }
 
          // End of parent element found!
@@ -185,7 +186,7 @@ static void XML_GetElement (struct XMLElement *ParentElem)
          if (ContentLength)
            {
             if ((ParentElem->Content = malloc (ContentLength + 1)) == NULL)
-               Lay_NotEnoughMemoryExit ();
+               Err_NotEnoughMemoryExit ();
             strncpy (ParentElem->Content,StartContent,ContentLength);
             ParentElem->Content[ContentLength] = '\0';
             ParentElem->ContentLength = ContentLength;
@@ -210,7 +211,7 @@ static void XML_GetElement (struct XMLElement *ParentElem)
          */
          /***** Allocate space for the child element *****/
          if ((ChildElem = calloc (1,sizeof (*ChildElem))) == NULL)
-            Lay_NotEnoughMemoryExit ();
+            Err_NotEnoughMemoryExit ();
 
          /***** Adjust XML elements pointers *****/
          if (ParentElem->FirstChild)	// This child is a brother of a former child
@@ -222,7 +223,7 @@ static void XML_GetElement (struct XMLElement *ParentElem)
          /***** Get child tag name *****/
          ChildElem->TagNameLength = strcspn (Gbl.XMLPtr,">/ \t");
          if ((ChildElem->TagName = malloc (ChildElem->TagNameLength + 1)) == NULL)
-            Lay_NotEnoughMemoryExit ();
+            Err_NotEnoughMemoryExit ();
          strncpy (ChildElem->TagName,Gbl.XMLPtr,ChildElem->TagNameLength);
          ChildElem->TagName[ChildElem->TagNameLength] = '\0';
          Gbl.XMLPtr += ChildElem->TagNameLength;
@@ -252,7 +253,7 @@ static void XML_GetElement (struct XMLElement *ParentElem)
                           Gbl.XMLPtr
             */
             if (*Gbl.XMLPtr != '>')	// Here it should be the end of start tag
-               Lay_ShowErrorAndExit ("XML syntax error. Expect &gt; ending unary tag.");
+               Err_ShowErrorAndExit ("XML syntax error. Expect &gt; ending unary tag.");
             Gbl.XMLPtr++;
             /*
             <parent><child/>...</parent>
@@ -312,7 +313,7 @@ static void XML_GetAttributes (struct XMLElement *Elem)
             EndOfStartTag = true;
            }
          else
-            Lay_ShowErrorAndExit ("XML syntax error. Expect &gt; ending unary tag with attributes.");
+            Err_ShowErrorAndExit ("XML syntax error. Expect &gt; ending unary tag with attributes.");
         }
       else if (*Gbl.XMLPtr == '>')	// End of start tag?
         {
@@ -320,7 +321,7 @@ static void XML_GetAttributes (struct XMLElement *Elem)
          EndOfStartTag = true;
         }
       else if (*Gbl.XMLPtr == '\0')
-         Lay_ShowErrorAndExit ("XML syntax error. Unexpected end of file.");
+         Err_ShowErrorAndExit ("XML syntax error. Unexpected end of file.");
       else
         {
          /* Start of attribute name:
@@ -331,7 +332,7 @@ static void XML_GetAttributes (struct XMLElement *Elem)
          */
          /***** Allocate space for the attribute *****/
          if ((Attribute = calloc (1,sizeof (*Attribute))) == NULL)
-            Lay_NotEnoughMemoryExit ();
+            Err_NotEnoughMemoryExit ();
 
          /***** Adjust XML element and attribute pointers *****/
          if (Elem->FirstAttribute)	// This attribute is a brother of a former attribute in current element
@@ -343,7 +344,7 @@ static void XML_GetAttributes (struct XMLElement *Elem)
          /***** Get attribute name *****/
          Attribute->AttributeNameLength = strcspn (Gbl.XMLPtr,"=");
          if ((Attribute->AttributeName = malloc (Attribute->AttributeNameLength + 1)) == NULL)
-            Lay_NotEnoughMemoryExit ();
+            Err_NotEnoughMemoryExit ();
          strncpy (Attribute->AttributeName,Gbl.XMLPtr,Attribute->AttributeNameLength);
          Attribute->AttributeName[Attribute->AttributeNameLength] = '\0';
          Gbl.XMLPtr += Attribute->AttributeNameLength;
@@ -371,11 +372,11 @@ static void XML_GetAttributes (struct XMLElement *Elem)
 	              "XML syntax error after attribute &quot;%s&quot;"
 	              " inside element &quot;%s&quot;.",
                       Attribute->AttributeName,Elem->TagName);
-            Lay_ShowErrorAndExit (ErrorTxt);
+            Err_ShowErrorAndExit (ErrorTxt);
            }
 
          if ((Attribute->Content = malloc (Attribute->ContentLength + 1)) == NULL)
-            Lay_NotEnoughMemoryExit ();
+            Err_NotEnoughMemoryExit ();
          strncpy (Attribute->Content,Gbl.XMLPtr,Attribute->ContentLength);
          Attribute->Content[Attribute->ContentLength] = '\0';
          Gbl.XMLPtr += Attribute->ContentLength;
@@ -477,14 +478,14 @@ void XML_PrintTree (struct XMLElement *ParentElem)
 bool XML_GetAttributteYesNoFromXMLTree (struct XMLAttribute *Attribute)
   {
    if (!Attribute->Content)
-      Lay_ShowErrorAndExit ("XML attribute yes/no not found.");
+      Err_ShowErrorAndExit ("XML attribute yes/no not found.");
    if (!strcasecmp (Attribute->Content,"yes") ||
        !strcasecmp (Attribute->Content,"y"))	// case insensitive, because users can edit XML
       return true;
    if (!strcasecmp (Attribute->Content,"no") ||
        !strcasecmp (Attribute->Content,"n"))	// case insensitive, because users can edit XML
       return false;
-   Lay_ShowErrorAndExit ("XML attribute yes/no not found.");
+   Err_ShowErrorAndExit ("XML attribute yes/no not found.");
    return false;	// Not reached
   }
 
diff --git a/swad_zip.c b/swad_zip.c
index 92eba0eb..8ebe25ab 100644
--- a/swad_zip.c
+++ b/swad_zip.c
@@ -38,6 +38,7 @@
 
 #include "swad_box.h"
 #include "swad_config.h"
+#include "swad_error.h"
 #include "swad_file_browser.h"
 #include "swad_form.h"
 #include "swad_global.h"
@@ -178,7 +179,7 @@ void ZIP_CreateZIPAsgWrk (void)
    /***** Change to directory of the assignments and works
           in order to start the path in the zip file from there *****/
    if (chdir (Path))
-      Lay_ShowErrorAndExit ("Can not change to temporary folder for compression.");
+      Err_ShowErrorAndExit ("Can not change to temporary folder for compression.");
 
    /***** Create public zip file with the assignment and works *****/
    snprintf (FileNameZIP,sizeof (FileNameZIP),"%s.zip",Txt_works_ZIP_FILE_NAME);
@@ -193,14 +194,14 @@ void ZIP_CreateZIPAsgWrk (void)
 
    /***** Return to the CGI directory *****/
    if (chdir (Cfg_PATH_CGI_BIN))
-      Lay_ShowErrorAndExit ("Can not change to cgi-bin folder.");
+      Err_ShowErrorAndExit ("Can not change to cgi-bin folder.");
 
    /***** If the zip command has been sucessful, write the link to zip file *****/
    if (Result == 0)
      {
       /***** Get file size *****/
       if (lstat (PathFileZIP,&FileStatus))	// On success ==> 0 is returned
-	 Lay_ShowErrorAndExit ("Can not get information about a file or folder.");
+	 Err_ShowErrorAndExit ("Can not get information about a file or folder.");
       else
 	{
 	 /***** Create URL pointing to ZIP file *****/
@@ -216,7 +217,7 @@ void ZIP_CreateZIPAsgWrk (void)
 	}
      }
    else
-      Lay_ShowErrorAndExit ("Can not compress files into zip file.");
+      Err_ShowErrorAndExit ("Can not compress files into zip file.");
 
    /***** Remove the directory of compression *****/
    Fil_RemoveTree (Path);
@@ -239,7 +240,7 @@ static void ZIP_CreateTmpDirForCompression (void)
    snprintf (PathDirTmp,sizeof (PathDirTmp),"%s/%s",
 	     Cfg_PATH_ZIP_PRIVATE,Gbl.FileBrowser.ZIP.TmpDir);
    if (mkdir (PathDirTmp,(mode_t) 0xFFF))
-      Lay_ShowErrorAndExit ("Can not create temporary folder for compression.");
+      Err_ShowErrorAndExit ("Can not create temporary folder for compression.");
   }
 
 /*****************************************************************************/
@@ -302,7 +303,7 @@ static void ZIP_CreateDirCompressionUsr (struct UsrData *UsrDat)
 	}
 
       if (!Success)
-	 Lay_ShowErrorAndExit ("Can not create temporary link for compression.");
+	 Err_ShowErrorAndExit ("Can not create temporary link for compression.");
      }
   }
 
@@ -373,13 +374,13 @@ static void ZIP_CompressFolderIntoZIP (void)
       /***** Change to directory of the clone folder
 	     in order to start the path in the zip file from there *****/
       if (chdir (PathCompression))
-	 Lay_ShowErrorAndExit ("Can not change to temporary folder for compression.");
+	 Err_ShowErrorAndExit ("Can not change to temporary folder for compression.");
 
       /***** Create public zip file with the assignment and works *****/
       if (asprintf (&FileNameZIP,"%s.zip",
 	            strcmp (Gbl.FileBrowser.FilFolLnk.Name,".") ? Gbl.FileBrowser.FilFolLnk.Name :
 							          Txt_ROOT_FOLDER_EXTERNAL_NAMES[Gbl.FileBrowser.Type]) < 0)
-         Lay_NotEnoughMemoryExit ();
+         Err_NotEnoughMemoryExit ();
       snprintf (PathFileZIP,sizeof (PathFileZIP),"%s/%s/%s/%s",
 	        Cfg_PATH_FILE_BROWSER_TMP_PUBLIC,
 	        Gbl.FileBrowser.TmpPubDir.L,
@@ -391,16 +392,16 @@ static void ZIP_CompressFolderIntoZIP (void)
 
       /***** Return to the CGI directory *****/
       if (chdir (Cfg_PATH_CGI_BIN))
-	 Lay_ShowErrorAndExit ("Can not change to cgi-bin folder.");
+	 Err_ShowErrorAndExit ("Can not change to cgi-bin folder.");
 
       /***** If the zip command has not been sucessful, abort *****/
       if (Result)
-	 Lay_ShowErrorAndExit ("Can not compress files into zip file.");
+	 Err_ShowErrorAndExit ("Can not compress files into zip file.");
 
       /***** If the zip command has been sucessful, write the link to zip file *****/
       /* Get file size */
       if (lstat (PathFileZIP,&FileStatus))	// On success ==> 0 is returned
-	 Lay_ShowErrorAndExit ("Can not get information about a file or folder.");
+	 Err_ShowErrorAndExit ("Can not get information about a file or folder.");
       else
 	{
 	 /* Create URL pointing to ZIP file */
@@ -480,7 +481,7 @@ static unsigned long long ZIP_CloneDir (const char *Path,const char *PathClone,c
 
 	    FileType = Brw_IS_UNKNOWN;
 	    if (lstat (PathFile,&FileStatus))	// On success ==> 0 is returned
-	       Lay_ShowErrorAndExit ("Can not get information about a file or folder.");
+	       Err_ShowErrorAndExit ("Can not get information about a file or folder.");
 	    else if (S_ISDIR (FileStatus.st_mode))		// It's a directory
 	       FileType = Brw_IS_FOLDER;
 	    else if (S_ISREG (FileStatus.st_mode))	// It's a regular file
@@ -498,7 +499,7 @@ static unsigned long long ZIP_CloneDir (const char *Path,const char *PathClone,c
 
 		  /***** Create clone of subdirectory *****/
 		  if (mkdir (PathFileClone,(mode_t) 0xFFF))
-		     Lay_ShowErrorAndExit ("Can not create temporary subfolder for compression.");
+		     Err_ShowErrorAndExit ("Can not create temporary subfolder for compression.");
 
 		  /***** Clone subtree starting at this this directory *****/
 		  FullSize += ZIP_CloneDir (PathFile,PathFileClone,PathFileInTree);
@@ -510,7 +511,7 @@ static unsigned long long ZIP_CloneDir (const char *Path,const char *PathClone,c
 
 		  /***** Create a symbolic link (clone) to original file *****/
 		  if (symlink (PathFile,PathFileClone) != 0)
-		     Lay_ShowErrorAndExit ("Can not create temporary link for compression.");
+		     Err_ShowErrorAndExit ("Can not create temporary link for compression.");
 
 		  /***** Update number of my views of this file *****/
 		  Brw_UpdateMyFileViews (Brw_GetFilCodByPath (PathFileInTree,false));	// Any file, public or not
@@ -519,7 +520,7 @@ static unsigned long long ZIP_CloneDir (const char *Path,const char *PathClone,c
 	   }
      }
    else
-      Lay_ShowErrorAndExit ("Error while scanning directory.");
+      Err_ShowErrorAndExit ("Error while scanning directory.");
 
    return FullSize;
   }