Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!usc!ucsd!ucbvax!bloom-beacon!SABER.COM!jimf
From: jimf@SABER.COM
Newsgroups: comp.windows.x
Subject: Re: How Do You Monitor Events For More Than 1 Display?
Message-ID: <9012031508.AA01432@armory>
Date: 3 Dec 90 15:08:03 GMT
Sender: daemon@athena.mit.edu (Mr Background)
Organization: The Internet
Lines: 42

|I am writing this program which is supposed to wait for KeyPress
|events from more than 1 display, however, after thinking about
|it for a long long time, I don't really know how to do it.
|Please enlighten me.

You should use select, something like this:

	#include <sys/types.h>
	#include <sys/time.h>

	fd_set readfds;

	FD_ZERO(&readfds);
	FS_SET(ConnectionNumber(display1), &readfds);
	FS_SET(ConnectionNumber(display2), &readfds);

	for (;;) {
	  switch(select(dtablesize(), &readfds, NULL, NULL, NULL)) {
	  case -1:
	    if (errno == EINTR)
	      continue;
	    perror("select");
	    exit(1);
	  case 0:
	    continue;
	  default:
	    if (FD_ISSET(ConnectionNumber(display1), &readfds)) {
	      while (XPending(display1))
	        XNextEvent(display1, &event);
	      /* do your thing here */
	    }
	    if (FD_ISSET(ConnectionNumber(display2), &readfds)) {
	      while (XPending(display1))
	        XNextEvent(display1, &event);
	      /* do your thing here */
	    }
	  }
	}

jim frost
saber software
jimf@saber.com