XIGrabDevice man page
XIGrabDevice, XIUngrabDevice — grab or ungrab the device.
Status XIGrabDevice( Display *display, int deviceid, Window grab_window, Time time, Cursor cursor, int grab_mode, int paired_device_mode, Bool owner_events, XIEventMask *mask);
Status XIUngrabDevice( Display *display, int deviceid, Time time);
cursor Specifies the cursor image to display for the duration of the grab.
display Specifies the connection to the X server.
deviceid Specifies the device that should be grabbed or ungrabbed.
grab_mode, paired_device_mode The grab mode for this device and (if applicable) the paired device.
grab_window The grab window.
mask Event mask.
owner_events True if events are to be reported normally.
time A valid timestamp or CurrentTime.
XIGrabDevice actively grabs control of the device. Further device events are reported only to the grabbing client. XIGrabDevice overrides any active device grab by this client.
If the device is an attached slave device, the device is automatically detached from the master device and reattached to the same master device when client ungrabs the device. If the master device is removed while the device is floating as a result of a grab, the device remains floating once the grab deactivates.
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 mask.
If the grab_mode argument is XIGrabModeAsync, device event processing continues as usual. If the device is currently frozen by this client, then processing of device events is resumed. If the grab_mode argument is XIGrabModeSync, 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 XIAllowEvents 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 paired_device_mode is XIGrabModeAsync, processing of events from the paired master device is unaffected by activation of the grab. If paired_device_mode is XIGrabModeSync, the state of the paired master device (as seen by client applications) appears to freeze, and the X server generates no further events from this device until the grabbing client issues a releasing XIAllowEvents 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 a slave device paired_device_mode is ignored.
If the device is actively grabbed by some other client, XIGrabDevice 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 cursor is not None this cursor is displayed until the client calls XIUngrabDevice.
XIGrabDevice can generate BadDevice, BadValue, and BadWindow errors.
The XIUngrabDevice request releases the device and any queued events if this client has it actively grabbed from either XIGrabDevice or XIGrabKey or XIGrabButton. 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. The X server automatically performs an XIUngrabDevice request if the event window for an active device grab becomes not viewable.
XIUngrabDevice can generate a BadDevice error.
BadValue A value is outside of the permitted range.
BadDevice An invalid device was specified. The device does not exist or is not a appropriate for the type of change.
BadMatch The window is not viewable.
BadWindow A value for a Window argument does not name a defined Window.
The protocol headers for XI 2.0 did not provide XIGrabModeAsync or XIGrabModeSync. Use GrabModeSync and GrabModeAsync instead, respectively.
XIUngrabDevice(3) is an alias of XIGrabDevice(3).