XIfEvent(3X11)              X Version 11(Release 5)              XIfEvent(3X11)


NAME
      XIfEvent, XCheckIfEvent, XPeekIfEvent - check the event queue with a
      predicate procedure

SYNTAX
      XIfEvent(display, event_return, predicate, arg)
            Display *display;
            XEvent *event_return;
            Bool (*predicate)();
            XPointer arg;

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

      XPeekIfEvent(display, event_return, predicate, arg)
            Display *display;
            XEvent *event_return;
            Bool (*predicate)();
            XPointer arg;

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

      display   Specifies the connection to the X server.

      event_return
                Returns either a copy of or  the matched event's associated
                structure.

      predicate Specifies the procedure that is to be called to determine if
                the next event in the queue matches what you want.

DESCRIPTION
      The XIfEvent function completes only when the specified predicate
      procedure returns True for an event, which indicates an event in the
      queue matches.  XIfEvent flushes the output buffer if it blocks waiting
      for additional events.  XIfEvent removes the matching event from the
      queue and copies the structure into the client-supplied XEvent structure.

      When the predicate procedure finds a match, XCheckIfEvent copies the
      matched event into the client-supplied XEvent structure and returns True.
      (This event is removed from the queue.)  If the predicate procedure finds
      no match, XCheckIfEvent returns False, and the output buffer will have
      been flushed.  All earlier events stored in the queue are not discarded.

      The XPeekIfEvent function returns only when the specified predicate
      procedure returns True for an event.  After the predicate procedure finds
      a match, XPeekIfEvent copies the matched event into the client-supplied


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XIfEvent(3X11)              X Version 11(Release 5)              XIfEvent(3X11)


      XEvent structure without removing the event from the queue.  XPeekIfEvent
      flushes the output buffer if it blocks waiting for additional events.

SEE ALSO
      XAnyEvent(3X11), XNextEvent(3X11), XPutBackEvent(3X11) XSendEvent(3X11)
      Xlib - C Language X Interface
















































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