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XSetErrorHandler(3)		XLIB FUNCTIONS		   XSetErrorHandler(3)

NAME
       XSetErrorHandler,   XGetErrorText,   XDisplayName,  XSetIOErrorHandler,
       XGetErrorDatabaseText - default error handlers

SYNTAX
       int (*XSetErrorHandler(int (*handler)(Display *,	XErrorEvent *)))();

       int XGetErrorText(Display *display, int code, char *buffer_return,  int
	      length);

       char *XDisplayName(_Xconst char *string);

       int (*XSetIOErrorHandler(int (*handler)(Display *)))();

       int XGetErrorDatabaseText(Display *display, _Xconst char	*name, _Xconst
	      char *message, _Xconst char  *default_string,  char  *buffer_re-
	      turn, int	length);

ARGUMENTS
       buffer_return
		 Returns the error description.

       code	 Specifies  the	 error code for	which you want to obtain a de-
		 scription.

       default_string
		 Specifies the default error message if	none is	found  in  the
		 database.

       display	 Specifies the connection to the X server.

       handler	 Specifies the program's supplied error	handler.

       length	 Specifies the size of the buffer.

       message	 Specifies the type of the error message.

       name	 Specifies the name of the application.

       string	 Specifies the character string.

DESCRIPTION
       Xlib  generally	calls the program's supplied error handler whenever an
       error is	received.  It is not called on BadName errors  from  OpenFont,
       LookupColor,  or	AllocNamedColor	protocol requests or on	BadFont	errors
       from a QueryFont	protocol request.   These  errors  generally  are  re-
       flected	back to	the program through the	procedural interface.  Because
       this condition is not assumed to	be fatal, it is	 acceptable  for  your
       error  handler  to return; the returned value is	ignored.  However, the
       error handler should not	call any functions (directly or	indirectly) on
       the  display that will generate protocol	requests or that will look for
       input events.  The previous error handler is returned.

       The XGetErrorText function copies a null-terminated  string  describing
       the  specified error code into the specified buffer.  The returned text
       is in the encoding of the current locale.  It is	recommended  that  you
       use  this function to obtain an error description because extensions to
       Xlib may	define their own error codes and error strings.

       The  XDisplayName  function  returns  the  name	of  the	 display  that
       XOpenDisplay  would  attempt  to	 use.	If a NULL string is specified,
       XDisplayName looks in the environment for the display and  returns  the
       display	name  that  XOpenDisplay  would	attempt	to use.	 This makes it
       easier to report	to the user precisely which display  the  program  at-
       tempted to open when the	initial	connection attempt failed.

       The  XSetIOErrorHandler	sets  the fatal	I/O error handler.  Xlib calls
       the program's supplied error handler if any sort	of system  call	 error
       occurs  (for  example, the connection to	the server was lost).  This is
       assumed to be a fatal condition,	and the	called routine should not  re-
       turn.  If the I/O error handler does return, the	client process exits.

       Note that the previous error handler is returned.

       The  XGetErrorDatabaseText  function  returns a null-terminated message
       (or the default message)	from the error message	database.   Xlib  uses
       this  function  internally  to look up its error	messages.  The text in
       the default_string argument is assumed to be in	the  encoding  of  the
       current locale, and the text stored in the buffer_return	argument is in
       the encoding of the current locale.

       The name	argument should	generally be the  name	of  your  application.
       The  message  argument  should indicate which type of error message you
       want.  If the name and message are not in the Host  Portable  Character
       Encoding, the result is implementation-dependent.  Xlib uses three pre-
       defined "application names" to report errors.  In these	names,	upper-
       case and	lowercase matter.

       XProtoError
		 The protocol error number is used as a	string for the message
		 argument.

       XlibMessage
		 These are the message strings that are	used internally	by the
		 library.

       XRequest	 For  a	core protocol request, the major request protocol num-
		 ber is	used for the message argument.	For an	extension  re-
		 quest,	 the  extension	 name (as given	by InitExtension) fol-
		 lowed by a period (.) and the minor request  protocol	number
		 is  used  for the message argument.  If no string is found in
		 the error database, the default_string	 is  returned  to  the
		 buffer	argument.

SEE ALSO
       XOpenDisplay(3),	XSynchronize(3)
       Xlib - C	Language X Interface

X Version 11			 libX11	1.6.12		   XSetErrorHandler(3)

NAME | SYNTAX | ARGUMENTS | DESCRIPTION | SEE ALSO

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