NAME
XGrabButton, XUngrabButton - grab pointer buttons
SYNTAX
int XGrabButton(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);
int XUngrabButton(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 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.
modifiers Specifies the set of keymasks or AnyModifier. The mask is
the bitwise inclusive OR of the valid keymask bits.
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 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 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), at which point a ButtonRelease event is
reported to the grabbing window.
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.
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
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 combinations, including the combination of no
modifiers. A button 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
generate this error.
BadWindow A value for a Window argument does not name a defined Window.
SEE ALSO
XAllowEvents(3), XGrabPointer(3), XGrabKey(3), XGrabKeyboard(3),
Xlib - C Language X Interface