NAME
XGrabKeyboard, XUngrabKeyboard - grab the keyboard
SYNTAX
int
XGrabKeyboard(Display * display, Window grab_window, Bool
owner_events, int pointer_mode, int keyboard_mode, Time
time);
int
XUngrabKeyboard(Display * display, Time time);
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.
- 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.
- time
- Specifies the time. You can pass either a timestamp or
CurrentTime.
DESCRIPTION
The
XGrabKeyboard function actively grabs control of the keyboard and
generates
FocusIn and
FocusOut events. Further key events are
reported only to the grabbing client.
XGrabKeyboard overrides any
active keyboard grab by this client. If owner_events is
False, all
generated key events are reported with respect to grab_window. If owner_events
is
True and if a generated key event would normally be reported to this
client, it is reported normally; otherwise, the event is reported with respect
to the grab_window. Both
KeyPress and
KeyRelease events are
always reported, independent of any event selection made by the client.
If the keyboard_mode argument is
GrabModeAsync, keyboard event processing
continues as usual. If the keyboard is currently frozen by this client, then
processing of keyboard events is resumed. If the keyboard_mode argument is
GrabModeSync, the state of the keyboard (as seen by client
applications) appears to freeze, and the X server generates no further
keyboard events until the grabbing client issues a releasing
XAllowEvents call or until the keyboard grab is released. Actual
keyboard changes are not lost while the keyboard is frozen; they are simply
queued in the server for later processing.
If pointer_mode is
GrabModeAsync, pointer event processing is unaffected
by activation of the grab. If pointer_mode is
GrabModeSync, the state
of the pointer (as seen by client applications) appears to freeze, and the X
server generates no further pointer events until the grabbing client issues a
releasing
XAllowEvents call or until the keyboard grab is released.
Actual pointer changes are not lost while the pointer is frozen; they are
simply queued in the server for later processing.
If the keyboard is actively grabbed by some other client,
XGrabKeyboard
fails and returns
AlreadyGrabbed. If grab_window is not viewable, it
fails and returns
GrabNotViewable. If the keyboard is frozen by an
active grab of another client, it fails and returns
GrabFrozen. If the
specified time is earlier than the last-keyboard-grab time or later than the
current X server time, it fails and returns
GrabInvalidTime. Otherwise,
the last-keyboard-grab time is set to the specified time (
CurrentTime
is replaced by the current X server time).
XGrabKeyboard can generate
BadValue and
BadWindow errors.
The
XUngrabKeyboard function releases the keyboard and any queued events
if this client has it actively grabbed from either
XGrabKeyboard or
XGrabKey.
XUngrabKeyboard does not release the keyboard and any
queued events if the specified time is earlier than the last-keyboard-grab
time or is later than the current X server time. It also generates
FocusIn and
FocusOut events. The X server automatically performs
an
UngrabKeyboard request if the event window for an active keyboard
grab becomes not viewable.
DIAGNOSTICS
- 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), XGrabKey(3), XGrabPointer(3)
Xlib - C Language X Interface