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Table of Contents
XGrabKeyboard, XUngrabKeyboard
- grab the keyboard
- int XGrabKeyboard(Display *display, Window grab_window,
- Bool owner_events, int pointer_mode, int keyboard_mode, Time time);
- int
XUngrabKeyboard(Display *display, Time time);
- 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.
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.
- 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.
XAllowEvents(3X11)
, XGrabButton(3X11)
, XGrabKey(3X11)
, XGrabPointer(3X11)
Xlib - C Language X Interface
Table of Contents
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