Comment 5 for bug 905456

(In reply to comment #2)
> Sounds like a bug in the application to me. From the GLX 1.4 spec (though
> that's certainly not new in 1.4):
> "A non-NULL return value for glXGetProcAddress does not guarantee that an
> extension function is actually supported at runtime. The client must also query
> glGetString() or glXQueryExtensionsString to determine if an extension is
> supported by a particular context."

I'm not sure what behaviour is correct. I relied on the the description of glXGetProcAddress:

"A NULL pointer is returned if function requested is not suported in the implementation being queried."