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XGetEventData(3)		 XLIB FUNCTIONS 		XGetEventData(3)

NAME
     XGetEventData,  XFreeEventData, XGenericEventCookie - retrieve and free ad-
     ditional event data through cookies.

SYNTAX
     Bool XGetEventData(Display *display, XGenericEventCookie *cookie);

     void XFreeEventData(Display *display, XGenericEventCookie *cookie);

ARGUMENTS
     display   Specifies the connection to the X server.

     cookie    Specifies the cookie to free or retrieve the data for.

STRUCTURES
     typedef struct {
	     int type;
	     unsigned long serial;
	     Bool send_event;
	     Display *display;
	     int extension;
	     int evtype;
	     unsigned int cookie;
	     void *data;
     } XGenericEventCookie;

DESCRIPTION
     Some extension XGenericEvents require additional memory to  store	informa-
     tion.   For  these events, the library returns a XGenericEventCookie with a
     token ('cookie') unique to  this  event.	The  XGenericEventCookie's  data
     pointer is undefined until XGetEventData is called.

     The  XGetEventData function retrieves this extra data for the given cookie.
     No round-trip to the server is required.  If the cookie is invalid  or  the
     event  is	not  an event handled by cookie handlers, False is returned.  If
     XGetEventData returns True, the cookie's data pointer points to the  memory
     containing  the  event  information.   A client must call XFreeEventData to
     free this memory.	XGetEventData returns False for multiple calls	for  the
     same event cookie.

     The  XFreeEventData  function  frees  the data associated with a cookie.  A
     client must call XFreeEventData for each cookie claimed with XGetEventData.

EXAMPLE CODE
     XEvent event;
     XGenericEventCookie *cookie = &ev;

     XNextEvent(display, &event);
     if (XGetEventData(display, cookie)) {
	 handle_cookie_event(cookie->data);
     } else
	 handle_event(&event);
     }
     XFreeEventData(display, cookie);

NOTES
     A cookie is defined as unclaimed if it has  been  returned  to  the  client
     through  XNextEvent  but its data has not been retrieved via XGetEventData.
     Subsequent calls to XNextEvent may free memory  associated  with  unclaimed
     cookies.  Multi-threaded X clients must ensure that XGetEventData is called
     before the next call to XNextEvent.

SEE ALSO
     XNextEvent(3),
     Xlib - C Language X Interface

X Version 11			  libX11 1.8.13 		XGetEventData(3)

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