void glXWaitX( void )
X rendering calls made prior to glXWaitX are guaranteed to be executed before GL rendering calls made after glXWaitX. Although the same result can be achieved using XSync, glXWaitX does not require a round trip to the server, and it is therefore more efficient in cases where client and server are on separate machines.
glXWaitX is ignored if there is no current GLX context.
glXWaitX may or may not flush the GL stream.
GLXBadCurrentWindow is generated if the drawable associated with the current context of the calling thread is a window, and that window is no longer valid.
glFinish, glFlush, glXWaitGL, XSync