XtAddEventHandler(3Xt) XtAddEventHandler(3Xt)
NAME
XtAddEventHandler, XtAddRawEventHandler,
XtRemoveEventHandler XtRemoveRawEventHandler - add and
remove event handlers
SYNOPSIS
void XtAddEventHandler(w, event_mask, nonmaskable,
proc, client_data)
Widget w;
EventMask event_mask;
Boolean nonmaskable;
XtEventHandler proc;
caddr_t client_data;
void XtAddRawEventHandler(w, event_mask, nonmaskable,
proc, client_data)
Widget w;
EventMask event_mask;
Boolean nonmaskable;
XtEventHandler proc;
caddr_t client_data;
void XtRemoveEventHandler(w, event_mask, nonmaskable,
proc, client_data)
Widget w;
EventMask event_mask;
Boolean nonmaskable;
XtEventHandler proc;
caddr_t client_data;
void XtRemoveRawEventHandler(w, event_mask,
nonmaskable, proc, client_data)
Widget w;
EventMask event_mask;
Boolean nonmaskable;
XtEventHandler proc;
caddr_t client_data;
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,
- 1 -
XtAddEventHandler(3Xt) XtAddEventHandler(3Xt)
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 is being registered.
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
XtAddEventHandler 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 XtRemoveEventHandler function stops the specified
procedure from receiving the specified events. The
request is ignored if client_data does not match the
value given in the call to XtAddEventHandler. If the
widget is realized, XtRemoveEventHandler calls
XSelectInput, if necessary. If the specified procedure
has not been registered, or if it has been registered
with a different value of client_data,
XtRemoveEventHandler returns without reporting an
error.
To stop a procedure from receiving any events, which
will remove it from the widget's event_table entirely,
call XtRemoveEventHandler with an event_mask of
XtAllEvents and with nonmaskable True.
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.
SEE ALSO
XtAppNextEvent(3Xt), XtBuildEventMask(3Xt)
X Toolkit Intrinsics Programming Manual
Xlib Programming Manual
- 2 -