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XSetErrorHandler(3X11)
X11R6
NAME
  XSetErrorHandler, XGetErrorText, XDisplayName, XSetIOErrorHandler,
  XGetErrorDatabaseText - default error handlers

SYNOPSIS
  int (*XSetErrorHandler(handler))()
	  int (*handler)(Display *, XErrorEvent *)

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

  char *XDisplayName(string)
	  char *string;

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

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

Index for Section 3X11

Alphabetical listing for X

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