X Window System routines: Extension routines

With X Window System Extension Routines, you can create extensions to the core Xlib functions with the same performance characteristics. The following list shows the protocol requests for X Window System extensions:

XQueryExtension
XListExtensions
XFreeExtensionList

Table 1 lists the X Window System Extension Routines and provides a short description of each routine.

Table 1. Extension routines
Routine	Description
XAllocID()	Returns a resource ID that can be used when creating new resources.
XESetCloseDisplay()	Defines a procedure to call when XCloseDisplay is called.
XESetCopyGC()	Defines a procedure to call when a GC is copied.
XESetCreateFont()	Defines a procedure to call when XLoadQueryFont is called.
XESetCreateGC()	Defines a procedure to call when a new GC is created.
XESetError()	Suppresses the call to an external error handling routine and defines an alternative routine for error handling.
XESetErrorString()	Defines a procedure to call when an I/O error is detected.
XESetEventToWire()	Defines a procedure to call when an event must be converted from the host to wire format.
XESetFreeFont()	Defines a procedure to call when XFreeFont is called.
XESetFreeGC()	Defines a procedure to call when a GC is freed.
XESetWireToEvent()	Defines a procedure to call when an event is converted from the wire to the host format.
XFreeExtensionList()	Frees memory allocated by XListExtensions.
XListExtensions()	Returns a list of all extensions supported by the server.
XQueryExtension()	Indicates whether a named extension is present.