Index for Section 3X11

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XSetDeviceFocus(3X11)
X11R6
NAME
  XSetDeviceFocus, XGetDeviceFocus - control extension input device focus

SYNOPSIS
  XSetDeviceFocus(display, device, focus, revert_to, time)
	  Display *display;
	  Display *device;
	  Window focus;
	  int revert_to;
	  Time time;

  XGetDeviceFocus(display, device, focus_return, revert_to_return,
  time_return)
	  Display *display;
	  Display *device;
	  Window *focus_return;
	  int *revert_to_return;
	  int *time_return;

ARGUMENTS
  display
      Specifies the connection to the X server.

  device
      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.

DESCRIPTION
  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 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 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. For those devices that support focus, XOpenDevice will return
  an XInputClassInfo structure with the input_class field equal to the
  constant FocusClass (defined in the file <XI.h>).

  XSetDeviceFocus can generate BadDevice, BadMatch, BadValue, and BadWindow
  errors.

  The XGetDeviceFocus 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 cannot be focused results in a BadMatch error.
  A device that can be focused returns information for input Class Focus when
  an XOpenDevice request is made.

  XGetDeviceFocus can generate BadDevice, and BadMatch errors.

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.

  BadMatch
	  This error may occur if an XGetDeviceFocus or XSetDeviceFocus
	  request was made specifying a device that the server implementation
	  does not allow to be focused.

SEE ALSO
  Programming with Xlib

Index for Section 3X11

Alphabetical listing for X

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