Manual Pages for UNIX Operating System command usage for man XDisplayName

XLIB FUNCTIONS                             XSetErrorHandler(3x11)



NAME
     XSetErrorHandler, XGetErrorText, XDisplayName, XSetIOEr-
     rorHandler, XGetErrorDatabaseText - default error handlers

SYNTAX
     cc [ flag... ] file... -lX11 [ library... ]

     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 proto-
     col 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 con-
     dition is not assumed to be fatal, it is acceptable for your



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XLIB FUNCTIONS                             XSetErrorHandler(3x11)



     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 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 condi-
     tion, 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



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XLIB FUNCTIONS                             XSetErrorHandler(3x11)



               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) followed 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(3x11), XSynchronize(3x11)
     Xlib - C Language X Interface


ATTRIBUTES
     See attributes(5) for descriptions of the following attri-
     butes:

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Availability                | x11/library/libx11          |
    |_____________________________|_____________________________|
    | Interface Stability         | Committed                   |
    |_____________________________|_____________________________|
    | MT-Level                    | See XInitThreads(3X11)      |
    |_____________________________|_____________________________|


























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