XT FUNCTIONS XtInsertEventTypeHandler(3xt)
NAME
XtInsertEventTypeHandler, XtRemoveEventTypeHandler, XtRe-
gisterExtensionSelector, XtSetEventDispatcher, XtDispatch-
EventToWidget - extension event handling
SYNTAXcc [ flag... ] file... -lXt [ library... ]
void XtInsertEventTypeHandler(Widget widget, int event_type,
XtPointer select_data, XtEventHandler proc, XtPointer
client_data, XtListPosition position);
void XtRemoveEventTypeHandler(Widget widget, int event_type,
XtPointer select_data, XtEventHandler proc, XtPointer
client_data);
void XtRegisterExtensionSelector(Display* display, intmin_event_type, int max_event_type, XtExtension-
SelectProc proc, XtPointer client_data);
XtEventDispatchProc XtSetEventDispatcher(Widget widget, intevent_type, XtEventDispatchProc proc);
Boolean XtDispatchEventToWidget(Widget widget, XEvent*
event); ARGUMENTS widget Specifies the widget for this event handler. Must be of class Core or any subclass thereof.event_type
Specifies the event type.select_data
Specifies data used to select or deselect events from the server. proc Specifies the proc.client_data
Specifies additional data to be passed to the event handler. position Specifies when the event handler is to be called relative to other previously registered handlers. display Specifies the display.min_event_type, max_event_type
Specifies the range of event types for this exten-
sion. X Version 11 Last change: libXt 1.0.8 1 XT FUNCTIONS XtInsertEventTypeHandler(3xt) event Specifies a pointer to the event to be dispatched.DESCRIPTION
The XtInsertEventTypeHandler function registers a procedure with the dispatch mechanism that is to be called when anevent that matches the specified event_type is dispatched to
the specified widget.If event_type is one of the core X protocol events then
select_data must be a pointer to a value of type EventMask,
indicating the event mask to be used to select for the desired event. This event mask will be included in thevalue returned by XtBuildEventMask. If the widget is real-
ized XtInsertEventTypeHandler calls XSelectInput if neces-
sary. Specifying NULL for select_data is equivalent to
specifying a pointer to an event mask containing 0. This is similar to the XtInsertRawEventHandler function.If event_type specifies an extension event type then the
semantics of the data pointed to by select_data are defined
by the extension selector registered for the specified event type. In either case the Intrinsics are not required to copy thedata pointed to by select_data, so the caller must ensure
that it remains valid as long as the event handler remainsregistered with this value of select_data.
The position argument allows the client to control the order of the invocation of event handlers registered for the same event type. If the client does not care about the order, it should normally specify XtListTail, which registers this event handler after any previously registered handlers for this event type. The XtRemoveEventTypeHandler function unregisters an even handler registered with XtInsertEventTypeHandler for thespecified event type. The request is ignored if client_data
does not match the value given with the handler was registered.If event_type specifies on of the core X protocol events,
select_data must be a pointer to a value of type EventMask,
indicating the mask to be used to deselect for the appropri-
ate event. If the widget is realized, XtRemoveEventType-
Handler calls XSelectInput if necessary. Specifying NULL forselect_data is equivalent to specifying a pointer to an
event mask containing 0. This is similar to the XtRemo-
veRawEventHandler function.If event_type specifies an extension event type then the
semantics of the data pointed to by select_data are defined
X Version 11 Last change: libXt 1.0.8 2 XT FUNCTIONS XtInsertEventTypeHandler(3xt) by the extension selector registered for the specified event type.The XtRegisterExtensionSelector function registers a pro-
cedure to arrange for the delivery of extension events to widgets.If min_event_type and max_event_type match the parameters to
a previous call to XtRegisterExtensionSelector for the samedisplay, the proc and client_data replace the previously
registered values. If the range specified by min_event_type
and max_event_type overlaps the range of the parameters to a
previous call for the same display in any other way, an error results. The XtSetEventDispatcher function registers the event dispatcher procedure specified by proc for events with thetype event_type. The previously registered dispatcher (or
the default dispatcher if there was no previously registereddispatcher) is returned. If proc is NULL, the default pro-
cedure is restored for the specified type. In the future, when XtDispatchEvent is called with an eventof event_type, the specified proc (or the default
dispatcher) will be invoked to determine a widget ot which to dispatch the event.The XtDispatchEventToWidget function scans the list of
registered event handlers for the specified widget and calls each handler that has been registered for the specifiedevent type, subject to the continue_to_dispatch value
returned by each handler. The Intrinsics behave as if event handlers were registered at the head of the list for Expose, NoExpose, GraphicsExpose, and VisibilityNotify events toinvoke the widget's expose procedure according to the expo-
sure compression rules and to update the widget's visiblefield if visible_interest is True. These internal event
handlers never set continue_to_dispatch to False.
XtDispatchEventToWidget returns True if any event handler
was called and False otherwise.SEE ALSO
XtGetKeyboardFocusWidget(3Xt)X Toolkit Intrinsics - C Language Interface
Xlib - C Language X Interface
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes: X Version 11 Last change: libXt 1.0.8 3 XT FUNCTIONS XtInsertEventTypeHandler(3xt)__________________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|___________________________________|
| Availability | x11/library/toolkit/libxt ||_____________________________|___________________________________|
| Interface Stability | Committed ||_____________________________|___________________________________|
| MT-Level | See XtToolkitThreadInitialize(3XT)|
|_____________________________|___________________________________|
X Version 11 Last change: libXt 1.0.8 4