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 ( RevertToParent,
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 (
CurrentTime 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