| ActiveTcl User Guide |

## Tcl/Tk Documentation > TkLib > HandleEvent

### Tcl/Tk Applications | Tcl Commands | Tk Commands | Tcl Library | Tk Library

### NAME

Tk_HandleEvent - invoke event handlers for window system events

### SYNOPSIS

#include <tk.h>
Tk_HandleEvent(eventPtr)

### ARGUMENTS

XEvent *eventPtr (in)
  Pointer to X event to dispatch to relevant handler(s). It is important that all unused fields of the structure be set to zero.

### DESCRIPTION

Tk_HandleEvent is a lower-level procedure that deals with window events. It is called by Tcl_ServiceEvent (and indirectly by Tcl_DoOneEvent), and in a few other cases within Tk. It makes callbacks to any window event handlers (created by calls to Tk_CreateEventHandler) that match eventPtr and then returns. In some cases it may be useful for an application to bypass the Tk event queue and call Tk_HandleEvent directly instead of calling Tcl_QueueEvent followed by Tcl_ServiceEvent.

This procedure may be invoked recursively. For example, it is possible to invoke Tk_HandleEvent recursively from a handler called by Tk_HandleEvent. This sort of operation is useful in some modal situations, such as when a notifier has been popped up and an application wishes to wait for the user to click a button in the notifier before doing anything else.

### KEYWORDS

callback, event, handler, window
Copyright © 1995-1997 Roger E. Critchlow Jr. Copyright © 1990-1992 The Regents of the University of California. Copyright © 1994-1996 Sun Microsystems, Inc.