X Version 11 (1 September 1988) XGrabButton(XS)
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 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).
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(XS), XGrabPointer(XS), XGrabKey(XS),
XGrabKeyboard(XS),
Xlib - C Language X Interface
(printed 2/12/90) (1 September 1988) XGrabButton(XS)