XGrabPointer(XS)  X Version 11 (Release 5) 6 January 1993   XGrabPointer(XS)


 Name

    XGrabPointer - grab the pointer

 Syntax


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

    XUngrabPointer(display, time)
          Display *display;
          Time time;

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


 Arguments


    confineto     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.

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

    grabwindow    Specifies the grab window.

    keyboardmode  Specifies further processing of keyboard events.  You can
                   pass GrabModeSync or GrabModeAsync.

    ownerevents   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.

    pointermode   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 ownerevents is False, all gen-
    erated pointer events are reported with respect to grabwindow and are
    reported only if selected by eventmask.  If ownerevents 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 grabwindow and is reported only if selected by eventmask.  For
    either value of ownerevents, unreported events are discarded.

    If the pointermode is GrabModeAsync, pointer event processing continues
    as usual.  If the pointer is currently frozen by this client, the pro-
    cessing of events for the pointer is resumed.  If the pointermode 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 keyboardmode is GrabModeAsync, keyboard event processing is unaf-
    fected by activation of the grab.  If the keyboardmode 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 grabwindow or one of its subwindows;
    otherwise, the cursor for grabwindow is displayed.

    If a confineto window is specified, the pointer is restricted to stay
    contained in that window.  The confineto window need have no relation-
    ship to the grabwindow.  If the pointer is not initially in the
    confineto window, it is warped automatically to the closest edge just
    before the grab activates and enter/leave events are generated as usual.
    If the confineto 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 applica-
    tion grabbed the pointer before its request was processed.

    XGrabPointer generates EnterNotify and LeaveNotify events.

    Either if grabwindow or confineto window is not viewable or if the
    confineto window lies completely outside the boundaries of the root win-
    dow, XGrabPointer fails and returns GrabNotViewable.  If the pointer is
    actively grabbed by some other client, it fails and returns Alread-
    yGrabbed.  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, XGrabBut-
    ton, 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 EnterNo-
    tify and LeaveNotify events.  The X server performs an UngrabPointer
    request automatically if the event window or confineto window for an
    active pointer grab becomes not viewable or if window reconfiguration
    causes the confineto window to lie completely outside the boundaries of
    the root window.

    The XChangeActivePointerGrab function changes the specified dynamic pa-
    rameters 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 pas-
    sive parameters of a XGrabButton.  The interpretation of eventmask 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 Cur-
                   sor.

    ``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 Win-
                   dow.

 See also

    XAllowEvents(XS), XGrabButton(XS), XGrabKey(XS), XGrabKeyboard(XS)
    Xlib - C Language X Interface