Tk_Grab(3) Tk Library Procedures Tk_Grab(3)

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NAME

Tk_Grab, Tk_Ungrab - manipulate grab state in an application

SYNOPSIS

#include <tk.h>

int
Tk_Grab(interp, tkwin, grabGlobal)

void
Tk_Ungrab(tkwin)

ARGUMENTS

Tcl_Interp *interp (in) Interpreter to use for
error reporting

Tk_Window tkwin (in) Window on whose behalf the
pointer is to be grabbed or
released

int grabGlobal (in) Boolean indicating whether
the grab is global or
application local
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DESCRIPTION

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 tkwin will be redirected to tkwin. If the
grab is global, then all mouse and keyboard events for windows
outside the tree rooted at tkwin (even those intended for windows in
other applications) will be redirected to tkwin. 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
tkwin) will be redirected.

Tk_Grab sets a grab on a particular window. Tkwin specifies the
window on whose behalf the pointer is to be grabbed. GrabGlobal
indicates whether the grab should be global or application local; if
it is non-zero, it means the grab should be global. Normally,
Tk_Grab returns TCL_OK; if an error occurs and the grab cannot be
set, TCL_ERROR is returned and an error message is left if interp's
result. Once this call completes successfully, no window outside the
tree rooted at tkwin 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.

Tk_Ungrab releases a grab on the mouse pointer and keyboard, if there
is one set on the window given by tkwin. Once a grab is released,
pointer and keyboard events will start being delivered to other
windows again.

KEYWORDS

grab, window

Tk Tk_Grab(3)