tk_createclientmessagehandler(3)
NAME
Tk_CreateClientMessageHandler, Tk_DeleteClientMessageHan
dler - 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 isn't handled by WM_PROTOCOL. Tk_Create
ClientMessageHandler 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_Han
dleEvent, the proc is called if it wasn't 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