Mastering Perl/Tk

Grab Methods

When a window does a grab, it holds all the keyboard and mouse input to itself. That window will not allow any other windows in the application to receive input. There is also a global grab, which means that no applications in the entire system can get input except the one window that has done the global grab. These methods are usually called from a Toplevel widget.

To do a local grab for the widget, use grab:

$widget->grab;

A local grab means that you can interact with other windows in the system, but not with other windows in the application. To do a global grab, use grabGlobal:

$widget->grabGlobal;

To ungrab, call grabRelease:

$widget->grabRelease;

To find out which widget has done a grab, call grabCurrent:

$who = $widget->grabCurrent;

To find out the current grab state of a $widget, call grabStatus:

$status = $widget->grabStatus;

The grabStatus method returns a string that is "none", "local", or "global".

To find out all the windows that are currently under the influence of grab, use grabs to get a list back:

@windows = $widget->grabs;