Specifies either the widget in the subtree structure which is to receive the
keyboard event, or
None.
Note that it is not an error to specify
None
when no input focus was previously set.
descendant
Specifies the widget for which the keyboard focus is to be set.
DESCRIPTION
If a future
KeyPress
or
KeyRelease
event occurs within the specified subtree,
XtSetKeyboardFocus
causes
XtDispatchEvent
to remap and send the event to the specified descendant widget.
When there is no modal cascade,
keyboard events can occur within a widget W in one of three ways:
*
W has the X input focus.
*
W has the keyboard focus of one of its ancestors,
and the event occurs within the ancestor or one of the ancestor's descendants.
*
No ancestor of W has a descendant within the keyboard focus,
and the pointer is within W.
When there is a modal cascade,
a widget W receives keyboard events if an ancestor of W is in the active
subset of the modal cascade and one or more of the previous conditions is
True.
When subtree or one of its descendants acquires the X input focus
or the pointer moves into the subtree such that keyboard events would
now be delivered to subtree, a
FocusIn
event is generated for the descendant if
FocusNotify
events have been selected by the descendant.
Similarly, when W loses the X input focus
or the keyboard focus for one of its ancestors, a
FocusOut
event is generated for descendant if
FocusNotify
events have been selected by the descendant.
SEE ALSO
XtCallAcceptFocus(3Xt)
X Toolkit Intrinsics - C Language Interface Xlib - C Language X Interface
