NAME

       XGrabPointer, XUngrabPointer, XChangeActivePointerGrab - grab the pointer

SYNTAX

       int  XGrabPointer(Display  *display,  Window  grab_window, Bool owner_events, unsigned int
              event_mask, int pointer_mode, int keyboard_mode, Window confine_to, Cursor  cursor,
              Time time);

       int XUngrabPointer(Display *display, Time time);

       int  XChangeActivePointerGrab(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.

       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 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 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(3), XGrabButton(3), XGrabKey(3), XGrabKeyboard(3)
       Xlib - C Language X Interface