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NAME

       XGrabPointer, XUngrabPointer, XChangeActivePointerGrab - grab the
       pointer

SYNTAX

       int XGrabPointer(Display *display, Window grab_window, Bool
              owner_events, unsigned int event_mask, int pointer_mode, int
              keyboard_mode, Window confine_to, Cursor cursor, Time time);

       int XUngrabPointer(Display *display, Time time);

       int XChangeActivePointerGrab(Display *display, unsigned int event_mask,
              Cursor cursor, Time time);

ARGUMENTS

       confine_to
                 Specifies the window to confine the pointer in or None.

       cursor    Specifies the cursor that is to be displayed during the grab
                 or None.

       display   Specifies the connection to the X server.

       event_mask
                 Specifies which pointer events are reported to the client.
                 The mask is the bitwise inclusive OR of the valid pointer
                 event mask bits.

       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 pointer
                 events are to be reported as usual or reported with respect
                 to the grab window if selected by the event mask.

       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 XGrabPointer function actively grabs control of the pointer and
       returns GrabSuccess if the grab was successful.  Further pointer events
       are reported only to the grabbing client.  XGrabPointer overrides any
       active pointer grab by this client.  If owner_events is False, all
       generated pointer events are reported with respect to grab_window and
       are reported only if selected by event_mask.  If owner_events is True
       and if a generated pointer event would normally be reported to this
       client, it is reported as usual.  Otherwise, the event is reported with
       respect to the grab_window and is reported only if selected by
       event_mask.  For either value of owner_events, unreported events are
       discarded.

       If the pointer_mode is GrabModeAsync, pointer event processing
       continues as usual.  If the pointer is currently frozen by this client,
       the processing of events for the pointer is resumed.  If the
       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 calls XAllowEvents or
       until the pointer 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_mode is GrabModeAsync, keyboard event processing is
       unaffected by activation of the grab.  If the keyboard_mode 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 calls XAllowEvents or until
       the pointer grab is released.  Actual keyboard changes are not lost
       while the pointer is frozen; they are simply queued in the server for
       later processing.

       If a cursor is specified, it is displayed regardless of what window the
       pointer is in.  If None is specified, the normal cursor for that window
       is displayed when the pointer is in grab_window or one of its
       subwindows; otherwise, the cursor for grab_window is displayed.

       If a confine_to window is specified, the pointer is restricted to stay
       contained in that window.  The confine_to window need have no
       relationship to the grab_window.  If the pointer is not initially in
       the confine_to window, it is warped automatically to the closest edge
       just before the grab activates and enter/leave events are generated as
       usual.  If the confine_to window is subsequently reconfigured, the
       pointer is warped automatically, as necessary, to keep it contained in
       the window.

       The time argument allows you to avoid certain circumstances that come
       up if applications take a long time to respond or if there are long
       network delays.  Consider a situation where you have two applications,
       both of which normally grab the pointer when clicked on.  If both
       applications specify the timestamp from the event, the second
       application may wake up faster and successfully grab the pointer before
       the first application.  The first application then will get an
       indication that the other application grabbed the pointer before its
       request was processed.

       XGrabPointer generates EnterNotify and LeaveNotify events.

       Either if grab_window or confine_to window is not viewable or if the
       confine_to window lies completely outside the boundaries of the root
       window, XGrabPointer fails and returns GrabNotViewable.  If the pointer
       is actively grabbed by some other client, it fails and returns
       AlreadyGrabbed.  If the pointer is frozen by an active grab of another
       client, it fails and returns GrabFrozen.  If the specified time is
       earlier than the last-pointer-grab time or later than the current X
       server time, it fails and returns GrabInvalidTime.  Otherwise, the
       last-pointer-grab time is set to the specified time (CurrentTime is
       replaced by the current X server time).

       XGrabPointer can generate BadCursor, BadValue, and BadWindow errors.

       The XUngrabPointer function releases the pointer and any queued events
       if this client has actively grabbed the pointer from XGrabPointer,
       XGrabButton, or from a normal button press.  XUngrabPointer does not
       release the pointer if the specified time is earlier than the last-
       pointer-grab time or is later than the current X server time.  It also
       generates EnterNotify and LeaveNotify events.  The X server performs an
       UngrabPointer request automatically if the event window or confine_to
       window for an active pointer grab becomes not viewable or if window
       reconfiguration causes the confine_to window to lie completely outside
       the boundaries of the root window.

       The XChangeActivePointerGrab function changes the specified dynamic
       parameters if the pointer is actively grabbed by the client and if the
       specified time is no earlier than the last-pointer-grab time and no
       later than the current X server time.  This function has no effect on
       the passive parameters of a XGrabButton.  The interpretation of
       event_mask and cursor is the same as described in XGrabPointer.

       XChangeActivePointerGrab can generate a BadCursor and BadValue error.

DIAGNOSTICS

       BadCursor A value for a Cursor argument does not name a defined Cursor.

       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), XGrabKeyboard(3)
       Xlib - C Language X Interface



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