'\"
'\" Copyright (c) 1998-2000 by Scriptics Corporation.
'\" All rights reserved.
'\"
.TH Tk_Grab 3 "" Tk "Tk Library Procedures"
.so man.macros
.BS
.SH NAME
Tk_Grab, Tk_Ungrab \- manipulate grab state in an application
.SH SYNOPSIS
.nf
\fB#include <tk.h>\fR
.sp
int
\fBTk_Grab\fR(\fIinterp, tkwin, grabGlobal\fR)
.sp
void
\fBTk_Ungrab\fR(\fItkwin\fR)
.SH ARGUMENTS
.AP Tcl_Interp *interp in
Interpreter to use for error reporting
.AP Tk_Window tkwin in
Window on whose behalf the pointer is to be grabbed or released
.AP int grabGlobal in
Boolean indicating whether the grab is global or application local
.BE
.SH DESCRIPTION
.PP
These functions are used to set or release a global or
application local grab.  When a grab is set on a particular window
in a Tk application, mouse and keyboard events can only be received by
that window and its descendants.  Mouse and keyboard events for
windows outside the tree rooted at \fItkwin\fR will be redirected to
\fItkwin\fR.  If the grab is global, then all mouse and keyboard
events for windows outside the tree rooted at \fItkwin\fR (even those
intended for windows in other applications) will be redirected to
\fItkwin\fR.  If the grab is application local, only mouse and
keyboard events intended for a windows within the same application
(but outside the tree rooted at \fItkwin\fR) will be redirected.
.PP
\fBTk_Grab\fR sets a grab on a particular window.  \fITkwin\fR
specifies the window on whose behalf the pointer is to be grabbed.
\fIGrabGlobal\fR indicates whether the grab should be global or
application local; if it is non-zero, it means the grab should be
global.  Normally, \fBTk_Grab\fR returns \fBTCL_OK\fR; if an error occurs
and the grab cannot be set, \fBTCL_ERROR\fR is returned and an error message
is left if \fIinterp\fR's result.  Once this call completes
successfully, no window outside the tree rooted at \fItkwin\fR will
receive pointer- or keyboard-related events until the next call to
Tk_Ungrab.  If a previous grab was in effect within the application,
then it is replaced with a new one.
.PP
\fBTk_Ungrab\fR releases a grab on the mouse pointer and keyboard, if
there is one set on the window given by \fItkwin\fR.  Once a grab is
released, pointer and keyboard events will start being delivered to
other windows again.
.SH KEYWORDS
grab, window