MirOS Manual: XtDispatchEventToWidget(3), XtInsertEventTypeHandler(3), XtRegisterExtensionSelector(3), XtRemoveEventTypeHandler(3), XtSetEventDispatcher(3)


XtInsertEventTypeHandler(3XXT FUNCTIXtInsertEventTypeHandler(3Xt)

NAME

     XtInsertEventTypeHandler, XtRemoveEventTypeHandler, XtRe-
     gisterExtensionSelector, XtSetEventDispatcher, XtDispatch-
     EventToWidget - extension event handling

SYNTAX

     void XtInsertEventTypeHandler(Widget wdget, int event_type,
          XtPointer select_data, XtEventHandler proc, XtPointer
          client_data, XtListPosition position);

     void XtRemoveEventTypeHandler(Widget wdget, int event_type,
          XtPointer select_data, XtEventHandler proc, XtPointer
          client_data);

     void XtRegisterExtensionSelector(Display* display, int
          min_event_type, int max_event_type, XtExtension-
          SelectProc proc, XtPointer client_data);

     XtEventDispatchProc XtSetEventDispatcher(Widget widget, int
          event_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.

     event     Specifies a pointer to the event to be dispatched.

XFree86                   Version 4.5.0                         1

XtInsertEventTypeHandler(3XXT FUNCTIXtInsertEventTypeHandler(3Xt)

DESCRIPTION

     The XtInsertEventTypeHandler function registeres a procedure
     with the dispatch mechanism that is to be called when an
     event 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 the value
     returned by XtBuildEventMask. If the widget is realized
     XtInsertEventTypeHandler calls XSelectInput if necessary.
     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 the
     data pointed to by select_data, so the caller must ensure
     that it remains valid as long as the event handler remains
     registered 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 the
     specified 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 for
     select_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
     by the extension selector registered for the specified event
     type.

XFree86                   Version 4.5.0                         2

XtInsertEventTypeHandler(3XXT FUNCTIXtInsertEventTypeHandler(3Xt)

     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 same
     display, 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 registes the event
     dispatcher procedure specified by proc for event swith the
     type event_type. The previously registered dispatcher (or
     the default dispatcher if there was no previousl registered
     dispatcher) 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 event
     of 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 specified
     event 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 to
     invoke the widget's expose procedure according to the expo-
     sure compression rules and to update the widget's visible
     field 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

XFree86                   Version 4.5.0                         3

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