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Old 06-12-2007, 01:12 AM   #1
Registered: Jun 2003
Distribution: Ubuntu, Debian
Posts: 40

Rep: Reputation: 15
Unhappy Using Xlib to monitor mouse and keyboard

Hi. I want to write a program using Xlib to monitor user activities including mouse and keyboard. I wrote the program. The strange thing is it only monitor part of the events.

I used XSelectInput to monitor several types of event. But only SubstructureNotifyMask events are displayed. Can anyone please help me why?? I can't realy figure it out.

Thanks in advance!!!

#include <X11/Xlib.h>

#include <stdio.h>
#include <stdlib.h>		/* getenv(), etc. */
#include <unistd.h>		/* sleep(), etc.  */

int main(int argc, char* argv[]) {
	Display* display;		/* pointer to X Display structure.           */
	int screen_num;		/* number of screen to place the window on.  */
	char *display_name = getenv("DISPLAY");  /* address of the X display.      */
	XEvent an_event;
	Window root_window;
	unsigned long events;
	XWindowAttributes attrs;

	static int count = 0;

	display = XOpenDisplay(display_name);
	if (display == NULL) {
		fprintf(stderr, "%s: cannot connect to X server '%s'\n",
				argv[0], display_name);

	screen_num = DefaultScreen(display);

	root_window = RootWindow(display, screen_num);

	XSync(display, False);

	XGetWindowAttributes (display, root_window, &attrs);
	XSelectInput(display, root_window, SubstructureNotifyMask | PointerMotionMask | KeyPressMask);
	while(1) {
		XNextEvent(display, &an_event);
		switch(an_event.type) {
		  case Expose:
 			//printf("called Expose event(%d)\n", count);
 			//printf("called default(%d)\n", count);
		printf("event.type: %d, (%d)\n", an_event.type, count);


	/* close the connection to the X server. */
	return 0;
Old 06-13-2007, 12:31 PM   #2
Amigo developer
Registered: Dec 2003
Location: Germany
Distribution: Slackware
Posts: 4,856

Rep: Reputation: 547Reputation: 547Reputation: 547Reputation: 547Reputation: 547Reputation: 547
Perhaps looking at the sources for the xev program would shed some light(I mean plagiarized code) on the matter.


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