The 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). causes the X server to generate and events.
Depending on the focus argument, the following occurs:
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If focus is all keyboard events are discarded until a new focus window is set, and the revert_to argument is ignored.
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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.
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If focus is 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 is called, or a 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:
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If revert_to is the focus reverts to the parent (or the closest viewable ancestor), and the new revert_to value is taken to be
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If revert_to is or the focus reverts to or respectively. When the focus reverts, the X server generates and events, but the last-focus-change time is not affected.
can generate and errors.
The function returns the focus window and the current focus state.