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