This section describes the commands that require special action from a device driver or are generally applicable to MCI drivers. Most MCI commands require obvious actions from the drivers (for example, MCI_STOP) and drivers can follow the behavior described in the MCI command specification.
This section also describes the procedures for adding new command messages or extending the existing ones. If you are writing a device driver that uses a command set already defined for the device type, you can use an existing command table to convert the command strings to command messages. When using a command table that is already defined, you only need to create the handler for the command messages. MCI will automatically translate the command strings to the command messages. In this case, the information you need to know is contained in the sections on handling MCI messages.
If your device driver extends command messages or adds new command messages, then you will need to write the message handler and extend the command tables. Writing the message handler is described in the sections on handling MCI messages. Creating a new message or extending a message is described in .