GLXContext glXGetCurrentContext( void )
glXGetCurrentContext returns the current context, as specified by
glXMakeCurrent. If there is no current context, NULL is returned.
glXGetCurrentContext returns client-side information. It does not make
a round trip to the server.
glXCreateContext, glXGetCurrentDisplay, glXGetCurrentDrawable,
glXMakeCurrent
GLXGETCURRENTCONTEXT(3G)