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XSetErrorHandler(3)		XLIB FUNCTIONS		   XSetErrorHandler(3)

NAME
       XSetErrorHandler, XGetErrorText,	XDisplayName, XSetIOErrorHandler, XSe-
       tIOErrorExitHandler, 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 *)))();

       void (*XSetIOErrorExitHandler(Display *display, void (*handler)(Display
	      *, void *), void *user_data))();

       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 normally
       not return.  If the I/O error handler does return, the  client  process
       exits  by default, this behavior	may be altered with the	XSetIOErrorEx-
       itHandler function.

       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	1.7.2		   XSetErrorHandler(3)

NAME | SYNTAX | ARGUMENTS | DESCRIPTION | SEE ALSO

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