XGrabPointer(3X) XGrabPointer(3X)
NAME
XGrabPointer, XUngrabPointer, XChangeActivePointerGrab
- grab the pointer
SYNOPSIS
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
confine_to
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.
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.
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XGrabPointer(3X) XGrabPointer(3X)
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.
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 owner_events is
False, all generated pointer events are reported with
respect to grab_window and are reported only if
selected by event_mask. If owner_events 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 grab_window and
is reported only if selected by event_mask. For either
value of owner_events, unreported events are discarded.
If the pointer_mode is GrabModeAsync, pointer event
processing continues as usual. If the pointer is
currently frozen by this client, the processing of
events for the pointer is resumed. If the pointer_mode
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 keyboard_mode is GrabModeAsync, keyboard event
processing is unaffected by activation of the grab. If
the keyboard_mode 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
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XGrabPointer(3X) XGrabPointer(3X)
what window the pointer is in. If None is specified,
the normal cursor for that window is displayed when the
pointer is in grab_window or one of its subwindows;
otherwise, the cursor for grab_window is displayed.
If a confine_to window is specified, the pointer is
restricted to stay contained in that window. The
confine_to window need have no relationship to the
grab_window. If the pointer is not initially in the
confine_to window, it is warped automatically to the
closest edge just before the grab activates and
enter/leave events are generated as usual. If the
confine_to 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 application grabbed the
pointer before its request was processed.
XGrabPointer generates EnterNotify and LeaveNotify
events.
Either if grab_window or confine_to window is not
viewable or if the confine_to window lies completely
outside the boundaries of the root window, XGrabPointer
fails and returns GrabNotViewable. If the pointer is
actively grabbed by some other client, it fails and
returns AlreadyGrabbed. 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, XGrabButton, or from a
normal button press. XUngrabPointer does not release
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XGrabPointer(3X) XGrabPointer(3X)
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 EnterNotify and
LeaveNotify events. The X server performs an
UngrabPointer request automatically if the event window
or confine_to window for an active pointer grab becomes
not viewable or if window reconfiguration causes the
confine_to window to lie completely outside the
boundaries of the root window.
The XChangeActivePointerGrab function changes the
specified dynamic parameters 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 passive parameters of a XGrabButton. The
interpretation of event_mask 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 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(3X11), XGrabButton(3X11), XGrabKey(3X11),
XGrabKeyboard(3X11)
Xlib Programming Manual
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