Man page or keyword search:   man All Sections 1 - General Commands 2 - System Calls 3 - Subroutines, Functions 4 - Special Files 5 - File Formats 6 - Games and Screensavers 7 - Macros and Conventions 8 - Maintenence Commands 9 - Kernel Interface New Commands Server 4.4BSD AIX Alpinelinux Archlinux Aros BSDOS BSDi Bifrost CentOS Cygwin Darwin Debian DigitalUNIX DragonFly ElementaryOS Fedora FreeBSD Gentoo GhostBSD HP-UX Haiku Hurd IRIX Inferno JazzOS Kali Knoppix LinuxMint MacOSX Mageia Mandriva Manjaro Minix MirBSD NeXTSTEP NetBSD OPENSTEP OSF1 OpenBSD OpenDarwin OpenIndiana OpenMandriva OpenServer OpenSuSE OpenVMS Oracle PC-BSD Peanut Pidora Plan9 QNX Raspbian RedHat Scientific Slackware SmartOS Solaris SuSE SunOS Syllable Tru64 UNIXv7 Ubuntu Ultrix UnixWare Xenix YellowDog aLinux   10987 pages apropos Keyword Search (all sections) Output format html ascii pdf view pdf save postscript

XCheckIfEvent()						       XCheckIfEvent()

Name
  XCheckIfEvent – check the event queue for a matching event; don't wait.

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

Arguments
  display   Specifies	a  connection  to  an  X  server;  returned  from
	    XOpenDisplay().

  event_return
	    Returns the matched event structure.

  predicate Specifies the procedure that is called to  determine  if  the
	    next event in the queue matches your criteria.

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

Returns
  True if a matching event is found, else False.

Description
  XCheckIfEvent() returns the next event in the queue that is matched  by
  the  specified  predicate  procedure.	  If found, that event is removed
  from the queue,  its	structure  is  copied  into  the  client-supplied
  XEvent,  and	True  is returned.  If no match is found, XCheckIfEvent()
  returns False and flushes the request	 buffer.   No  other  events  are
  removed from the queue.  Later events in the queue are not searched.

  The  predicate  procedure  is called with the arguments display, event,
  and arg.

  For more information, see Volume One, Chapter 8, Events.

See Also
  XQLength(),  XAllowEvents(),	 XCheckMaskEvent(),   XCheckTypedEvent(),
  XCheckTypedWindowEvent(),  XCheckWindowEvent(),  XEventsQueued(), XGet‐
  InputFocus(),	 XGetMotionEvents(),  XIfEvent(),   XMaskEvent(),   XNex‐
  tEvent(),  XPeekEvent(),  XPeekIfEvent(),  XPending(), XPutBackEvent(),
  XSelectInput(), XSendEvent(), XSetInputFocus(),  XSynchronize(),  XWin‐
  dowEvent().

Xlib - Input Handling					       XCheckIfEvent()

Vote for polarhome