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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(char *string);

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

       int XGetErrorDatabaseText(Display *display, char	*name, char *message,
	      char *default_string, char *buffer_return, int length);

ARGUMENTS
       buffer_return
		 Returns the error description.

       code	 Specifies the error code for which you	want to	obtain a
		 description.

       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
       reflected 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 indi-
       rectly) 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
       attempted 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
       return.	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
		 request, 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	1.6.5		   XSetErrorHandler(3)

NAME | SYNTAX | ARGUMENTS | DESCRIPTION | SEE ALSO

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