Table of Contents
XGrabKey, XUngrabKey -
grab keyboard keys
- int XGrabKey(Display *display, int keycode, unsigned
int
- modifiers, Window grab_window, Bool owner_events, int pointer_mode,
int keyboard_mode);
- int XUngrabKey(Display *display, int keycode, unsigned
int
- modifiers, Window grab_window);
- display
- Specifies the connection
to the X server.
- grab_window
- Specifies the grab window.
- keyboard_mode
- Specifies
further processing of keyboard events. You can pass GrabModeSync or GrabModeAsync.
- keycode
- Specifies the KeyCode or AnyKey.
- modifiers
- Specifies the set of
keymasks or AnyModifier. The mask is the bitwise inclusive OR of the valid
keymask bits.
- owner_events
- Specifies a Boolean value that indicates whether
the keyboard events are to be reported as usual.
- pointer_mode
- Specifies
further processing of pointer events. You can pass GrabModeSync or GrabModeAsync.
The XGrabKey function establishes a passive grab on the
keyboard. In the future, the keyboard is actively grabbed (as for XGrabKeyboard),
the last-keyboard-grab time is set to the time at which the key was pressed
(as transmitted in the KeyPress event), and the KeyPress event is reported
if all of the following conditions are true:
- The keyboard is not grabbed
and the specified key (which can itself be a modifier key) is logically
pressed when the specified modifier keys are logically down, and no other
modifier keys are logically down.
- Either the grab_window is an ancestor
of (or is) the focus window, or the grab_window is a descendant of the
focus window and contains the pointer.
- A passive grab on the same key combination
does not exist on any ancestor of grab_window.
The interpretation of the
remaining arguments is as for XGrabKeyboard. The active grab is terminated
automatically when the logical state of the keyboard has the specified
key released (independent of the logical state of the modifier keys).
Note
that the logical state of a device (as seen by client applications) may
lag the physical state if device event processing is frozen.
A modifiers
argument of AnyModifier is equivalent to issuing the request for all
possible modifier combinations (including the combination of no modifiers).
It is not required that all modifiers specified have currently assigned
KeyCodes. A keycode argument of AnyKey is equivalent to issuing the request
for all possible KeyCodes. Otherwise, the specified keycode must be in the
range specified by min_keycode and max_keycode in the connection setup,
or a BadValue error results.
If some other client has issued a XGrabKey
with the same key combination on the same window, a BadAccess error
results. When using AnyModifier or AnyKey, the request fails completely,
and a BadAccess error results (no grabs are established) if there is
a conflicting grab for any combination.
XGrabKey can generate BadAccess,
BadValue, and BadWindow errors.
The XUngrabKey function releases
the key combination on the specified window if it was grabbed by this client.
It has no effect on an active grab. A modifiers of AnyModifier is equivalent
to issuing the request for all possible modifier combinations (including
the combination of no modifiers). A keycode argument of AnyKey is equivalent
to issuing the request for all possible key codes.
XUngrabKey can generate
BadValue and BadWindow error.
- BadAccess
- A client attempted
to grab a key/button combination already grabbed by another client.
- BadValue
- Some numeric value falls outside the range of values accepted by the
request. Unless a specific range is specified for an argument, the full
range defined by the argument's type is accepted. Any argument defined as
a set of alternatives can generate this error.
- BadWindow
- A value for a
Window argument does not name a defined Window.
XAllowAccess(3X11)
,
XGrabButton(3X11)
, XGrabKeyboard(3X11)
, XGrabPointer(3X11)
Xlib - C Language X Interface
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