NAME¶
Tk_CreateClientMessageHandler, Tk_DeleteClientMessageHandler - associate
procedure callback with ClientMessage type X events
SYNOPSIS¶
#include <tk.h>
Tk_CreateClientMessageHandler(proc)
Tk_DeleteClientMessageHandler(proc)
ARGUMENTS¶
- Tk_ClientMessageProc *proc (in)
- Procedure to invoke whenever a ClientMessage X event occurs
on any display.
DESCRIPTION¶
Tk_CreateClientMessageHandler arranges for
proc to be invoked in
the future whenever a ClientMessage X event occurs that is not handled by
WM_PROTOCOL.
Tk_CreateClientMessageHandler is intended for use
by applications which need to watch X ClientMessage events, such as drag and
drop applications.
The callback to
proc will be made by
Tk_HandleEvent; this
mechanism only works in programs that dispatch events through
Tk_HandleEvent (or through other Tk procedures that call
Tk_HandleEvent, such as
Tk_DoOneEvent or
Tk_MainLoop).
Proc should have arguments and result that match the type
Tk_ClientMessageProc:
typedef int Tk_ClientMessageProc(
Tk_Window tkwin,
XEvent * eventPtr);
The
tkwin parameter to
proc is the Tk window which is associated
with this event.
EventPtr is a pointer to the X event.
Whenever an X ClientMessage event is processed by
Tk_HandleEvent, the
proc is called if it was not handled as a
WM_PROTOCOL. The
return value from
proc is normally 0. A non-zero return value indicates
that the event is not to be handled further; that is,
proc has done all
processing that is to be allowed for the event.
If there are multiple ClientMessage event handlers, each one is called for each
event, in the order in which they were established.
Tk_DeleteClientMessageHandler may be called to delete a
previously-created ClientMessage event handler: it deletes each handler it
finds that matches the
proc argument. If no such handler exists, then
Tk_DeleteClientMessageHandler returns without doing anything. Although
Tk supports it, it's probably a bad idea to have more than one callback with
the same
proc argument.
KEYWORDS¶
bind, callback, event, handler