XtAddEventHandler(3Xt) XT FUNCTIONS XtAddEventHandler(3Xt)
NAME
XtAddEventHandler, XtAddRawEventHandler, XtRemoveEvent-
Handler, XtRemoveRawEventHandler, XtInsertEventHandler,
XtInsertRawEventHandler - add and remove event handlers
SYNTAX
void XtAddEventHandler(Widget w, EventMask event_mask,
Boolean nonmaskable, XtEventHandler proc, XtPointer
client_data);
void XtAddRawEventHandler(Widget w, EventMask event_mask,
Boolean nonmaskable, XtEventHandler proc, XtPointer
client_data);
void XtRemoveEventHandler(Widget w, EventMask event_mask,
Boolean nonmaskable, XtEventHandler proc, XtPointer
client_data);
void XtRemoveRawEventHandler(Widget w, EventMask event_mask,
Boolean nonmaskable, XtEventHandler proc, XtPointer
client_data);
void XtInsertEventHandler(Widget w, EventMask event_mask,
Boolean nonmaskable, XtEventHandler proc, XtPointer
client_data, XtListPosition position);
void XtInsertRawEventHandler(Widget w, EventMask event_mask,
Boolean nonmaskable, XtEventHandler proc, XtPointer
client_data, XtListPosition position);
typedef enum { XtListHead, XtListTail } XtListPosition;
ARGUMENTS
client_data
Specifies additional data to be passed to the
client's event handler.
event_mask
Specifies the event mask for which to call or
unregister this procedure.
nonmaskable
Specifies a Boolean value that indicates whether
this procedure should be called or removed on the
nonmaskable events (GraphicsExpose, NoExpose,
SelectionClear, SelectionRequest, SelectionNotify,
ClientMessage, and MappingNotify).
proc Specifies the procedure that is to be added or
removed.
w Specifies the widget for which this event handler
XFree86 Version 4.5.0 1
XtAddEventHandler(3Xt) XT FUNCTIONS XtAddEventHandler(3Xt)
is being registered.
position Specifies when the event handler is to be called
relative to other previously registered handlers.
DESCRIPTION
The XtAddEventHandler function registers a procedure with
the dispatch mechanism that is to be called when an event
that matches the mask occurs on the specified widget. If the
procedure is already registered with the same client_data,
the specified mask is ORed into the existing mask. If the
widget is realized, XtAddEventHandler calls XSelectInput, if
necessary.
The XtAddRawEventHandler function is similar to XtAddEvent-
Handler except that it does not affect the widget's mask and
never causes an XSelectInput for its events. Note that the
widget might already have those mask bits set because of
other nonraw event handlers registered on it.
The XtRemoveRawEventHandler function stops the specified
procedure from receiving the specified events. Because the
procedure is a raw event handler, this does not affect the
widget's mask and never causes a call on XSelectInput.
XtInsertEventHandler is identical to XtAddEventHandler with
the additional position argument. if position is XtListHead,
the event handler is registered to that it will be called
before any event handlers that were previously registered
for the same widget. If position is XtListTail, the event
handler is registered to be called after any previously
registered event handlers. If the procedure is already
registered with the same client_data value, the specified
mask augments the existing mask and the procedure is reposi-
tioned in the list.
XtInsertRawEventHandler is similar to XtInsertEventHandler
except that it does not modify the widget's event mask and
never causes an XSelectInput for the specified events. If
the procedure is already registered with the same
client_data value, the specified mask augments the existing
mask and the procedure is repositioned in the list.
SEE ALSO
XtAppNextEvent(3Xt), XtBuildEventMask(3Xt)
X Toolkit Intrinsics - C Language Interface
Xlib - C Language X Interface
XFree86 Version 4.5.0 2