Manual pages › X Window and screen libraries (3X)

XGrButton(3X)

grab pointer buttons

From the original Amiga UNIX 2.1 manual. Some things it mentions may not be in this release.

NAME

XGrabButton, XUngrabButton - 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.

confine_to

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 XWIN 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.

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

XWIN 3.0               Last change: 9/1/88                 .ie t

     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.

DESCRIPTION

The XGrabButton function establishes a passive grab.  In the
future, the pointer is actively grabbed (as for XGrab-
Pointer), the last-pointer-grab time is set to the time at
which the button was pressed (as transmitted in the But-
tonPress 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 grab_window contains the pointer.

• The confine_to window (if any) is viewable.

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

     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 combinations (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 possible buttons.  Otherwise, it is not required that
     the specified button currently be assigned to a physical
     button.

XWIN 3.0               Last change: 9/1/88                 .ie t

     If some other client has already issued a XGrabButton with
     the same button/key combination on the same window, a BadAc-
     cess error results.  When using AnyModifier or AnyButton,
     the request fails completely, and a BadAccess error results
     (no grabs are established) if there is a conflicting 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 combi-
nations, 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 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 gen-
          erate this error.

BadWindow A value for a Window argument does not name a