The WH_JOURNALPLAYBACK hook enables an application to insert messages into the system message queue. You can use this hook to play back a series of mouse and keyboard events recorded earlier by using the WH_JOURNALRECORD hook. Regular mouse and keyboard input is disabled as long as a WH_JOURNALPLAYBACK hook is installed. A WH_JOURNALPLAYBACK hook is a global hook ¾ it cannot be used as a thread-specific hook.
The WH_JOURNALPLAYBACK hook returns a time-out value. This value tells the system how many milliseconds to wait before processing the current message from the playback hook. This enables the hook to control the timing of the events it plays back.
For more information, see the JournalPlaybackProc function.