xref: /xsrc/external/mit/libXi/dist/man/XGrabDevice.txt

XGRABDEVICE(libmansuffix)
=========================

NAME
----

   XGrabDevice, XUngrabDevice - grab/release the specified
   extension device

SYNOPSIS
--------

   #include <X11/extensions/XInput.h>

   int XGrabDevice( Display *display,
                    XDevice* device,
                    Window grab_window,
                    Bool owner_events,
                    int event_count,
                    XEventClass *event_list,
                    int this_device_mode,
                    int other_devices_mode,
                    Time time);

   int XUngrabDevice( Display *display,
                      XDevice *device,
                      Time time);

   display
          Specifies the connection to the X server.

   device
          Specifies the device to be grabbed or released.

   grab_window
          Specifies the id of a window to be associated with the
          device.

   owner_events
          Specifies a Boolean value that indicates whether
          the events from the device are to be reported as usual or
          reported with respect to the grab window if selected by
          the event list.

   event_count
          Specifies the number of elements in the event_list
          array.

   event_list
          Specifies a pointer to a list of event classes that
          indicates which events the client wishes to receive.
          These event classes must have been obtained specifying
          the device being grabbed.

   this_device_mode
          Specifies further processing of events from this
          device. You can pass GrabModeSync or GrabModeAsync.

   other_devices_mode
          Specifies further processing of events from other
          devices. You can pass GrabModeSync or GrabModeAsync.

   time
          Specifies the time. You can pass either a timestamp or
          CurrentTime.

DESCRIPTION
-----------

   The XGrabDevice request actively grabs control of the device
   and generates DeviceFocusIn and DeviceFocusOut events. Further
   device events are reported only to the grabbing
   client. XGrabDevice overrides any active device grab by this
   client. event_list is a pointer to a list of event classes.
   This list indicates which events the client wishes to receive
   while the grab is active. If owner_events is False, all
   generated device events are reported with respect to
   grab_window if selected. If owner_events is True and if a
   generated device event would normally be reported to this
   client, it is reported normally; otherwise, the event is
   reported with respect to the grab_window, and is only reported
   if specified in the event_list.

   If the this_device_mode argument is GrabModeAsync, device event
   processing continues as usual. If the device is currently
   frozen by this client, then processing of device events is
   resumed. If the this_device_mode argument is GrabModeSync, the
   state of the device (as seen by client applications) appears to
   freeze, and the X server generates no further device events
   until the grabbing client issues a releasing XAllowDeviceEvents
   call or until the device grab is released. Actual device
   changes are not lost while the device is frozen; they are
   simply queued in the server for later processing.

   If other_devices_mode is GrabModeAsync, processing of events
   from other devices is unaffected by activation of the grab. If
   other_devices_mode is GrabModeSync, the state of all devices
   except the grabbed device (as seen by client applications)
   appears to freeze, and the X server generates no further events
   from those devices until the grabbing client issues a releasing
   XAllowDeviceEvents call or until the device grab is released.
   Actual events are not lost while the devices are frozen; they
   are simply queued in the server for later processing.

   If the device is actively grabbed by some other client,
   XGrabDevice fails and returns AlreadyGrabbed. If grab_window is
   not viewable, it fails and returns GrabNotViewable. If the
   device is frozen by an active grab of another client, it fails
   and returns GrabFrozen. If the specified time is earlier than
   the last-device-grab time or later than the current X server
   time, it fails and returns GrabInvalidTime. Otherwise, the
   last-device-grab time is set to the specified time
   (CurrentTime is replaced by the current X server time).

   If a grabbed device is closed by a client while an active grab
   by that client is in effect, the active grab is released. If
   the device is frozen only by an active grab of the requesting
   client, it is thawed.

   XGrabDevice can generate BadClass, BadDevice, BadValue, and
   BadWindow errors.

   The XUngrabDevice request releases the device and any queued
   events if this client has it actively grabbed from either
   XGrabDevice or XGrabDeviceKey. If other devices are frozen by
   the grab, XUngrabDevice thaws them. XUngrabDevice does not
   release the device and any queued events if the specified time
   is earlier than the last-device-grab time or is later than the
   current X server time. It also generates DeviceFocusIn and
   DeviceFocusOut events. The X server automatically performs an
   UngrabDevice request if the event window for an active device
   grab becomes not viewable.

   XUngrabDevice can generate a BadDevice error.

DIAGNOSTICS
-----------

   BadDevice
          An invalid device was specified. The specified device
          does not exist or has not been opened by this client via
          XOpenInputDevice. This error may also occur if the
          specified device is the X keyboard or X pointer device.

   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
--------

   XAllowDeviceEvents(libmansuffix), XGrabDeviceButton(libmansuffix), XGrabDeviceKey(libmansuffix)