Specifies the device whose focus is to be queried or
changed.
focus
Specifies the window, PointerRoot, FollowKeyboard, or
None.
focus_return
Returns the focus window, PointerRoot, FollowKeyboard, or
None.
revert_to
Specifies where the input focus reverts to if the window
becomes not viewable. You can pass RevertToParent,
RevertToPointerRoot, RevertToFollowKeyboard, or RevertToNone.
revert_to_return
Returns the current focus state RevertToParent,
RevertToPointerRoot, RevertToFollowKeyboard, or RevertToNone.
time_return
Returns the last_focus_time for the device.
time
Specifies the time. You can pass either a timestamp or
CurrentTime.
The XSetDeviceFocus request changes the focus of the specified
device and its last-focus-change time. It has no effect if the
specified time is earlier than the current last-focus-change time
or is later than the current X server time. Otherwise, the
last-focus-change time is set to the specified time CurrentTime is
replaced by the current X server time). XSetDeviceFocus(3)
causes the X server to generate DeviceFocusIn and DeviceFocusOut
events.
Depending on the focus argument, the following
occurs:
If focus is None , all device events are discarded until
a new focus window is set, and the revert_to argument is
ignored.
If focus is a window, it becomes the device's focus
window. If a generated device event would normally be reported to
this window or one of its inferiors, the event is reported as
usual. Otherwise, the event is reported relative to the focus
window.
If focus is PointerRoot, the focus window is dynamically
taken to be the root window of whatever screen the pointer is on at
each event from the specified device. In this case, the
revert_to argument is ignored.
If focus is FollowKeyboard, the focus window is
dynamically taken to be the window to which the X keyboard focus is
set at each input event.
The specified focus window must be viewable at the time
XSetDeviceFocus(3) is called, or a BadMatch error
results. If the focus window later becomes not viewable, the X
server evaluates the revert_to argument to determine the new
focus window as follows:
If revert_to is RevertToParent, the focus reverts to the
parent (or the closest viewable ancestor), and the new revert_to
value is taken to be RevertToNone.
If revert_to is RevertToPointerRoot,
RevertToFollowKeyboard, or RevertToNone, the focus reverts to
PointerRoot, FollowKeyboard, or None, respectively.
When the focus reverts, the X server generates DeviceFocusIn and
DeviceFocusOut events, but the last-focus-change time is not
affected.
Input extension devices are not required to support the ability
to be focused. Attempting to set the focus of a device that does
not support this request will result in a BadMatch error. Whether
or not given device can support this request can be determined by
the information returned by XOpenDevice(3). For those
devices that support focus, XOpenDevice(3) will return
an XInputClassInfo structure with the input_class
field equal to the constant FocusClass (defined in the file
<X11/XI.h>).
XSetDeviceFocus(3) can generate BadDevice,
BadMatch, BadValue, and BadWindow errors.
The XGetDeviceFocus(3) request returns the focus
window and the current focus state.
Not all input extension devices can be focused. Attempting to
query the focus state of a device that can't be focused results in
a BadMatch error. A device that can be focused returns information
for input Class Focus when an XOpenDevice(3) request is
made.
XGetDeviceFocus(3) can generate BadDevice, and
BadMatch errors.
An invalid device was specified. The specified device does not
exist or has not been opened by this client with
XOpenInputDevice(). This error might 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.
BadMatch
This error might occur if an XGetDeviceFocus(3) or
XSetDeviceFocus(3) request was made specifying a
device that the server implementation does not allow to be
focused.