MirOS Manual: XGetDeviceFocus(3), XSetDeviceFocus(3)

XSetDeviceFocus(3X11)      X FUNCTIONS      XSetDeviceFocus(3X11)


     XSetDeviceFocus, XGetDeviceFocus - control extension input
     device focus


     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;


     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, FollowKey-
                 board, or None.

                 Returns the focus window, PointerRoot, Follow-
                 Keyboard, or None.

     revert_to   Specifies where the input focus reverts to if
                 the window becomes not viewable. You can pass
                 RevertToParent, RevertToPointerRoot, RevertTo-
                 FollowKeyboard, or RevertToNone.

                 Returns the current focus state RevertToParent,
                 RevertToPointerRoot, RevertToFollowKeyboard, or

     time_return Returns the last_focus_time for the device.

     time        Specifies the time. You can pass either a times-
                 tamp or CurrentTime.


     The XSetDeviceFocus request changes the focus of the speci-
     fied device and its last-focus-change time. It has no effect
     if the specified time is earlier than the current last-

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XSetDeviceFocus(3X11)      X FUNCTIONS      XSetDeviceFocus(3X11)

     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 gen-
     erate 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 dynami-
          cally taken to be the root window of whatever screen
          the pointer is on at each event from the specified dev-
          ice. In this case, the revert_to argument is ignored.

     +    If focus is FollowKeyboard, the focus window is dynami-
          cally 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, RevertToFollowKey-
          board, or RevertToNone, the focus reverts to Pointer-
          Root, 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 dev-
     ice that does not support this request will result in a Bad-
     Match 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, XOpenDev-
     ice will return an XInputClassInfo structure with the

XFree86                   Version 4.5.0                         2

XSetDeviceFocus(3X11)      X FUNCTIONS      XSetDeviceFocus(3X11)

     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 can't be focused
     results in a BadMatch error.  A device that can be focused
     returns information for input Class Focus when an XOpenDev-
     ice request is made.

     XGetDeviceFocus can generate BadDevice, and BadMatch errors.


     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.


     Programming with Xlib

XFree86                   Version 4.5.0                         3

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