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


 Name

    XGrabButton - grab pointer buttons

 Syntax


    XGrabButton(display, button, modifiers, grab_window, owner_events,
                event_mask, pointer_mode, keyboard_mode, confine_to, cursor)
          Display *display;
          unsigned int button;
          unsigned int modifiers;
          Window grab_window;
          Bool owner_events;
          unsigned int event_mask;
          int pointer_mode, keyboard_mode;
          Window confine_to;
          Cursor cursor;

    XUngrabButton(display, button, modifiers, grab_window)
          Display *display;
          unsigned int button;
          unsigned int modifiers;
          Window grab_window;


 Arguments


    button         Specifies the pointer button that is to be grabbed or
                   released or AnyButton.

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

    cursor         Specifies the cursor that is to be displayed 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.

    modifiers      Specifies the set of keymasks or AnyModifier.  The mask is
                   the bitwise inclusive OR of the valid keymask bits.

    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.

 Description

    The XGrabButton function establishes a passive grab.  In the future, the
    pointer is actively grabbed (as for XGrabPointer), the last-pointer-grab
    time is set to the time at which the button was pressed (as transmitted
    in the ButtonPress event), and the ButtonPress event is reported if all
    of the following conditions are true:

    +  The pointer is not grabbed, and the specified button is logically
       pressed when the specified modifier keys are logically down, and no
       other buttons or modifier keys are logically down.

    +  The grabwindow contains the pointer.

    +  The confineto window (if any) is viewable.

    +  A passive grab on the same button/key combination does not exist on
       any ancestor of grabwindow.

    The interpretation of the remaining arguments is as for XGrabPointer.
    The active grab is terminated automatically when the logical state of the
    pointer has all buttons released (independent of the state of the logical
    modifier keys).

    Note that the logical state of a device (as seen by client applications)
    may lag the physical state if device event processing is frozen.

    This request overrides all previous grabs by the same client on the same
    button/key combinations on the same window.  A modifiers of AnyModifier
    is equivalent to issuing the grab request for all possible modifier com-
    binations (including the combination of no modifiers).  It is not
    required that all modifiers specified have currently assigned KeyCodes.
    A button of AnyButton is equivalent to issuing the request for all possi-
    ble buttons.  Otherwise, it is not required that the specified button
    currently be assigned to a physical button.

    If some other client has already issued a XGrabButton with the same
    button/key combination on the same window, a ``BadAccess'' error results.
    When using AnyModifier or AnyButton, the request fails completely, and a
    ``BadAccess'' error results (no grabs are established) if there is a con-
    flicting grab for any combination.  XGrabButton has no effect on an
    active grab.

    XGrabButton can generate ``BadCursor'', ``BadValue'', and ``BadWindow''
    errors.

    The XUngrabButton function releases the passive button/key combination on
    the specified window if it was grabbed by this client.  A modifiers of
    AnyModifier is equivalent to issuing the ungrab request for all possible
    modifier combinations, including the combination of no modifiers.  A but-
    ton of AnyButton is equivalent to issuing the request for all possible
    buttons.  XUngrabButton has no effect on an active grab.

    XUngrabButton can generate ``BadValue'' and ``BadWindow'' errors.

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