Provided by: libx11-doc_1.6.9-2ubuntu1.6_all 
NAME
XSetInputFocus, XGetInputFocus - control input focus
SYNTAX
int XSetInputFocus(Display *display, Window focus, int revert_to, Time time);
int XGetInputFocus(Display *display, Window *focus_return, int *revert_to_return);
ARGUMENTS
display Specifies the connection to the X server.
focus Specifies the window, PointerRoot, or None.
focus_return
Returns the focus window, PointerRoot, or None.
revert_to Specifies where the input focus reverts to if the window becomes not viewable. You can pass
RevertToParent, RevertToPointerRoot, or RevertToNone.
revert_to_return
Returns the current focus state RevertToPointerRoot, or RevertToNone).
time Specifies the time. You can pass either a timestamp or CurrentTime.
DESCRIPTION
The XSetInputFocus function changes the input focus and the 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 is replaced by the
current X server time). XSetInputFocus causes the X server to generate FocusIn and FocusOut events.
Depending on the focus argument, the following occurs:
• If focus is None, all keyboard 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 keyboard's focus window. If a generated keyboard 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 keyboard event. In this case, the revert_to argument is ignored.
The specified focus window must be viewable at the time XSetInputFocus 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 or RevertToNone, the focus reverts to PointerRoot or None,
respectively. When the focus reverts, the X server generates FocusIn and FocusOut events, but the
last-focus-change time is not affected.
XSetInputFocus can generate BadMatch, BadValue, and BadWindow errors.
The XGetInputFocus function returns the focus window and the current focus state.
DIAGNOSTICS
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
XWarpPointer(3) Xlib - C Language X Interface