/*
 * Routine to let user select a window using the mouse
 */

Window Select_Window(dpy)
     Display *dpy;
{
  int status;
  Cursor cursor;
  XEvent event;
  Window target_win = None, root = RootWindow(dpy,screen);
  int buttons = 0;

  /* Make the target cursor */
  cursor = XCreateFontCursor(dpy, XC_crosshair);

  /* Grab the pointer using target cursor, letting it room all over */
  status = XGrabPointer(dpy, root, False,
			ButtonPressMask|ButtonReleaseMask, GrabModeSync,
			GrabModeAsync, root, cursor, CurrentTime);
  if (status != GrabSuccess) Fatal_Error("Can't grab the mouse.");

  /* Let the user select a window... */
  while ((target_win == None) || (buttons != 0)) {
    /* allow one more event */
    XAllowEvents(dpy, SyncPointer, CurrentTime);
    XWindowEvent(dpy, root, ButtonPressMask|ButtonReleaseMask, &event);
    switch (event.type) {
    case ButtonPress:
      if (target_win == None) {
	target_win = event.xbutton.subwindow; /* window selected */
	if (target_win == None) target_win = root;
      }
      buttons++;
      break;
    case ButtonRelease:
      if (buttons > 0) /* there may have been some down before we started */
	buttons--;
       break;
    }
  } 

  XUngrabPointer(dpy, CurrentTime);      /* Done with pointer */

  return(target_win);
}