Linux Certif

Toute la documentation sur la certification Linux LPI

XGrabDevice

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
        theevents from the deviceare to be reported as usual or
        reported with respect to the grab windowif 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 eventsthe client wishes to receive.
        These event classes must have beenobtained specifying
        the device being grabbed.
 

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

 other_devices_mode
        Specifies further processing of events from other
        devices.You can pass GrabModeSyncor 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(3), XGrabDeviceButton(3), XGrabDeviceKey(3)