Search code examples
c++x11blocking

XPending Function Is Blocking

I have a program that has the following basic structure:

while( true )
{
    // get any X11 events
    while( XPending( display ) > 0 )
    {
       // get an event using XNextEvent and do stuff with it
    }

    // draw to the display
 }

The program is rendering an opengl scene. The problem I am having is that when I click and start dragging on the window, the XPending call get blocks until i finish the drag sequence, thus halting any animations that were in progress. I can solve this solution by having another thread send Expose events and thus waking up the XPending call, but ideally I would like to have an X function that checks for events but does not block at all.

Solution

  • If you just want to process received events without blocking to wait for more, use XEventsQueued(display, QueuedAlready) instead of XPending(display).