Messages sent to windows. These are processed by window functions and are similar to the messages defined in the WINDOWS.H header file. The Multimedia extensions messages that are sent to windows all have an MM_ prefix.The messages in the Multimedia extensions fall into two broad categories:
Messages sent to windows. These are processed by window functions and are similar to the messages defined in the WINDOWS.H header file. The Multimedia extensions messages that are sent to windows all have an MM_ prefix.
Messages specific to a callback function or message-based API. These include Media Control Interface command messages, which an application sends to communicate with MCI, as well as messages sent to callback functions.
All the Multimedia extensions messages have a related set of parameters. This chapter describes each message in detail.