The Wait, Notify, and Test Flags
[The feature associated with this page, MCI, is a legacy feature. It has been superseded by MediaPlayer. MediaPlayer has been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer instead of MCI, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]
Most MCI commands include flags that modify the command. The "wait" (MCI_WAIT) and "notify" (MCI_NOTIFY) flags are common to every command. The "test" (MCI_TEST) flag is available to digital-video and VCR devices. The following topics describe the use of these flags.