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From: bjaspan@athena.mit.edu (Barr3y Jaspan)
Newsgroups: comp.windows.x
Subject: Ignoring XSendEvents *other* than by checking send_event
Message-ID: <1990Jul8.195537.18395@athena.mit.edu>
Date: 8 Jul 90 19:55:37 GMT
Sender: daemon@athena.mit.edu (Mr Background)
Reply-To: bjaspan@athena.mit.edu (Barr3y Jaspan)
Organization: Massachusetts Institute of Technology
Lines: 85

I wrote a small program that takes a list of window ids and forwards all the
events it receives to each window on the list using XSendEvent.  I know the
program works because if I run two copies, I can send events from one to the
other and everything happens correctly.  However, I have been unable to get any
other program to recognize the resent events.  This article is
specifically about
getting X Toolkit programs to accept the events.

I wrote a simple X Toolkit application that creates a single button, and then I
ran it under Saber-C tracing _XtwaitForSomething.  Sure enough, the
program runs
until it hits the select() and waits for something to happen.  If I move the
cursor into the button, select() returns and the program goes merrily on it's
way.  When I send events to the window with my program, however, *select never
returns*.  The events are simply not getting sent to the client.  I have
run the
test under twm and uwm (to see if the reason had to do with reparenting).

I thought the only was to ignore artifical events was to check the send_event
field and ignore the event if it was set, but obivously this is not the case. 
What am I missing?  The source code for my event-duplicating program (which I
call xfork) is below.

Barr3y Jaspan
Student Information Processing Board (SIPB)

---- snip snip ----

#include <stdio.h>
#include <X11/Xlib.h>

main(argc, argv)
   int argc;
   char **argv;
{
     Display *dpy;
     Window window;
     Window wins[100];
     int num_wins, i;
     XEvent event;


     argc -= 1;
     num_wins = 0;
     while (argc > 0) {
	  wins[num_wins] = atoi(argv[num_wins+1]);
	  printf("wins[%d] = %d\n", num_wins, wins[num_wins]);
	  num_wins += 1;
	  argc -= 1;
     }
     
     dpy = XOpenDisplay(NULL);

     window =
	  XCreateSimpleWindow(dpy,
			      RootWindow(dpy, DefaultScreen(dpy)),
			      0, 0,
			      100, 100,
			      2,
			      WhitePixel(dpy, DefaultScreen(dpy)),
			      BlackPixel(dpy, DefaultScreen(dpy)));

     XSelectInput(dpy, window, 0xffffff);
     XMapWindow(dpy, window);
     while (1) {
	  XNextEvent(dpy, &event);
	  if (event.type == Expose) break;
     }

     printf("got expose\n");
     
     while (1) {
	  XNextEvent(dpy, &event);
	  printf("got event\n");
	  printf("forwarding\n");
	  for (i=0; i < num_wins; i++)
	       printf("%d\n", XSendEvent(dpy, wins[i], False,
					 0xffffff, &event)); 
     }

     /* NOTREACHED */
     return 0;
}