This manual page is for Mac OS X version 10.6.3

Reading manual pages

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 Bad-Font BadFont
       Font errors from a QueryFont protocol request.  These errors generally are reflected back to the pro-gram program
       gram 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 han-dler handler
       dler should not call any functions (directly or indirectly) on the display that will generate proto-col protocol
       col 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 pre-cisely precisely
       cisely 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 predefined ``application
       names'' to report errors.  In these names, uppercase 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 number is used for the message
                 argument.  For an extension request, the extension name (as given by InitExtension) fol-lowed followed
                 lowed by a period (.) and the minor request protocol number is used for the message argu-ment. argument.
                 ment.  If no string is found in the error database, the default_string is returned to the
                 buffer argument.

SEE ALSO
       XOpenDisplay(3X11), XSynchronize(3X11)
       Xlib - C Language X Interface



X Version 11                                    libX11 1.2.1                             XSetErrorHandler(3)