Avoiding multiple Exposure

You don't want to redraw the window more than is necessary. If a window receives 2 expose events and nothing happens in between, the window needn't be drawn twice. Strategies are

• Ignore all Expose events whose count field isn't zero.
• Since all expose events generated by a single user action are guarenteed to be contiguous in the queue, you can discard all but the first.

If you want to remove all expose events relating to a certain window, use

XEvent event;
...
case Expose:
  /* deal with event */
  while XCheckTypedWindowEvent(display,window,Expose,&event)
        ;