XtInsertEventHandler()XtInsertEventHandler()NameXtInsertEventHandler - register an event handler procedure that
receives events before or after all previously registered event han‐
dlers.
Synopsisvoid XtInsertEventHandler(w, event_mask, nonmaskable, proc, client_data, posi‐
tion)
Widget w;
EventMask event_mask;
Boolean nonmaskable;
XtEventHandler proc;
XtPointer client_data;
XtListPosition position;
Inputs
w Specifies the widget for which this event handler is being
registered. Must be of class core or any subclass thereof.
event_mask
Specifies the event mask for which to call this procedure.
nonmaskable
Specifies whether this procedure should be called on nonmask‐
able events
proc Specifies the procedure that is to be called.
client_data
Specifies additional data to be passed to the client's event
handler.
position Specifies when the event handler is to be called relative to
other previously registered handlers.
Availability
Release 4 and later.
DescriptionXtInsertEventHandler() registers the procedure proc and the data
client_data with the Intrinsics event dispatching mechanism. When an
event of one of the types set in event_mask occurs on the window of the
widget w, proc will be invoked and client_data passed as one of its
arguments.
The argument position specifies where in the list of event handlers
proc should be inserted. If it is XtListHead, proc will be inserted at
the beginning of the list and will be called before all previously reg‐
istered handlers. If it is XtListTail, proc will be inserted at the
end of the list and will be called after all previously registered han‐
dlers.
If the procedure is already registered with the same client_data, the
specified event_mask augments the existing mask, and the procedure is
repositioned in the list according to position.
XtInsertEventHandler() is identical to XtAddEventHandler() with the
additional position argument. See XtAddEventHandler() for more infor‐
mation.
See XtEventHandler(2) for an explanation of how to write an event han‐
dler procedure.
Usage
Neither applications nor widgets often need to use event handlers.
Using action procedures and translation tables provides a more flexible
way to respond to input events.
Structures
The XtListPosition type is as follows.
typedef enum {
XtListHead,
XtListTail
} XtListPosition;
See XtAddEventHandler() for a list of bits that can be set in the
event_mask argument.
See AlsoXtAddEventHandler(1), XtAddRawEventHandler(1), XtInsertRawEven‐
tHandler(1), XtRemoveEventHandler(1), XtRemoveRawEventHandler(1).
Xt - Event Handling XtInsertEventHandler()
