Some considerations

[Martijn Sipkema]

>  > Well, I meant native X11 rendering. I think from the above definition
>  > using glFlush() to have the compositing manager update the
>  > framebuffer for single buffered GLX clients is correct
>
>  In theory yes, in practice... there are applications out there which do
>  calls to glFlush at the weirdest times.  And others that don't even
>  bother.

Those are bugs and will be fixed once proper use of glFlush() is required.

>  > but I don't think there's an equivalent to glFlush() in the core X11
>  > rendering, is there?
>
>  From XFlush(3x)
>
>    The XFlush function flushes the output buffer.  Most client applica-
>    tions need not use this function because the output buffer is automati-
>    cally flushed as needed by calls to XPending, XNextEvent, and XWindow-
>    Event.  Events generated by the server may be enqueued into the
>    library's event queue.
>
>    The XSync function flushes the output buffer and then waits until all
>    requests have been received and processed by the X server.  Any errors
>    generated must be handled by the error handler.  For each protocol
>    error received by Xlib, XSync calls the client application's error han-
>    dling routine (see section 11.8.2).  Any events generated by the server
>    are enqueued into the library's event queue.
>
>    Finally, if you passed False, XSync does not discard the events in the
>    queue.  If you passed True, XSync discards all events in the queue,
>    including those events that were on the queue before XSync was called.
>    Client applications seldom need to call XSync.

But does XFlush()/XSync() cause a request or is it handled completely in
Xlib?

--ms