Windows PowerShell command on Get-command grab

Manual Pages for UNIX Operating System command usage for man grab

Tk Built-In Commands grab(1T)

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NAME

grab - Confine pointer and keyboard events to a window sub-

tree

SYNOPSIS

grab ?-global? window

grab option ?arg arg ...?

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DESCRIPTION

This command implements simple pointer and keyboard grabs

for Tk. Tk's grabs are different than the grabs described

in the Xlib documentation. When a grab is set for a partic-

ular window, Tk restricts all pointer events to the grab

window and its descendants in Tk's window hierarchy. When-

ever the pointer is within the grab window's subtree, the

pointer will behave exactly the same as if there had been no

grab at all and all events will be reported in the normal

fashion. When the pointer is outside window's tree, button presses and releases and mouse motion events are reported to window, and window entry and window exit events are ignored.

The grab subtree ``owns'' the pointer: windows outside the

grab subtree will be visible on the screen but they will be

insensitive until the grab is released. The tree of windows

underneath the grab window can include top-level windows, in

which case all of those top-level windows and their descen-

dants will continue to receive mouse events during the grab.

Two forms of grabs are possible: local and global. A local

grab affects only the grabbing application: events will be

reported to other applications as if the grab had never

occurred. Grabs are local by default. A global grab locks

out all applications on the screen, so that only the given

subtree of the grabbing application will be sensitive to

pointer events (mouse button presses, mouse button releases, pointer motions, window entries, and window exits). During

global grabs the window manager will not receive pointer

events either.

During local grabs, keyboard events (key presses and key

releases) are delivered as usual: the window manager con-

trols which application receives keyboard events, and if

they are sent to any window in the grabbing application then

they are redirected to the focus window. During a global

grab Tk grabs the keyboard so that all keyboard events are

always sent to the grabbing application. The focus command

is still used to determine which window in the application

receives the keyboard events. The keyboard grab is released

Tk Last change: 1

Tk Built-In Commands grab(1T)

when the grab is released.

Grabs apply to particular displays. If an application has windows on multiple displays then it can establish a

separate grab on each display. The grab on a particular

display affects only the windows on that display. It is possible for different applications on a single display to

have simultaneous local grabs, but only one application can

have a global grab on a given display at once.

The grab command can take any of the following forms:

grab ?-global? window

Same as grab set, described below.

grab current ?window?

If window is specified, returns the name of the current

grab window in this application for window's display,

or an empty string if there is no such window. If win-

dow is omitted, the command returns a list whose ele-

ments are all of the windows grabbed by this applica-

tion for all displays, or an empty string if the appli-

cation has no grabs.

grab release window

Releases the grab on window if there is one, otherwise

does nothing. Returns an empty string.

grab set ?-global? window

Sets a grab on window. If -global is specified then

the grab is global, otherwise it is local. If a grab

was already in effect for this application on window's display then it is automatically released. If there is

already a grab on window and it has the same

global/local form as the requested grab, then the com-

mand does nothing. Returns an empty string.

grab status window

Returns none if no grab is currently set on window,

local if a local grab is set on window, and global if a

global grab is set.

WARNING

It is very easy to use global grabs to render a display com-

pletely unusable (e.g. by setting a grab on a widget which

does not respond to events and not providing any mechanism

for releasing the grab). Take extreme care when using them!

BUGS

It took an incredibly complex and gross implementation to

produce the simple grab effect described above. Given the

current implementation, it isn't safe for applications to Tk Last change: 2

Tk Built-In Commands grab(1T)

use the Xlib grab facilities at all except through the Tk

grab procedures. If applications try to manipulate X's grab

mechanisms directly, things will probably break.

If a single process is managing several different Tk appli-

cations, only one of those applications can have a local

grab for a given display at any given time. If the applica-

tions are in different processes, this restriction doesn't exist.

EXAMPLE

Set a grab so that only one button may be clicked out of a

group. The other buttons are unresponsive to the mouse until the middle button is clicked.

pack [button .b1 -text "Click me! #1" -command {destroy .b1}]

pack [button .b2 -text "Click me! #2" -command {destroy .b2}]

pack [button .b3 -text "Click me! #3" -command {destroy .b3}]

grab .b2

KEYWORDS

grab, keyboard events, pointer events, window

ATTRIBUTES

See attributes(5) for descriptions of the following attri-

butes:

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| ATTRIBUTE TYPE | ATTRIBUTE VALUE|

|____________________|__________________|_

| Availability | runtime/tk-8 |

|____________________|__________________|_

| Interface Stability| Uncommitted |

|____________________|_________________|

NOTES Source for Tk is available on http://opensolaris.org. Tk Last change: 3