🚀 go-pugleaf

Here is another possible solution for processing until some event has
occurred (ie. until the `S' key has been pressed):

======================================================================
SYNTAX
     Bool XCheckIfEvent(display, event_return, predicate, arg)
           Display *display;
           XEvent *event_return;
           Bool (*predicate)();
           char *arg;

ARGUMENTS
     arg       Specifies the user-supplied argument that will be
               passed to the predicate procedure.

     display   Specifies the connection to the X server.

     event_return
               Returns either a copy of or  the matched event's
               associated structure.

     predicate Specifies the procedure that is to be called to
               determine if the next event in the queue matches
               what you want.

DESCRIPTION
     When the predicate procedure finds a match, XCheckIfEvent
     copies the matched event into the client-supplied XEvent
     structure and returns True.  (This event is removed from the
     queue.) If the predicate procedure finds no match, XCheckI-
     fEvent returns False, and the output buffer will have been
     flushed.  All earlier events stored in the queue are not
     discarded.
======================================================================

So, inside your processing loop, add a call to XCheckIfEvent():

	while (! XCheckIfEvent (...)) {
	   what_ever_code_goes_here;
	}

I used this for an X-based talk program so you can conference calls
with multiple users on multiple displays.  I wanted to poll various
displays/windows in a round robin fashion looking for input from one
user that needed to be distributed that as output to the other users
(so they can see what you just typed).

-Walter Rowe  <rowe@cme.nist.gov>