NAME
XGrabKey, XUngrabKey - grab keyboard keys
SYNTAX
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);
ARGUMENTS
- 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.
DESCRIPTION
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), at which point a
KeyRelease event is reported to
the grabbing window.
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.
DIAGNOSTICS
- 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.
SEE ALSO
XAllowEvents(3), XGrabButton(3), XGrabKeyboard(3), XGrabPointer(3)
Xlib - C Language X Interface