Entry-Point Functions

In addition to the installable driver entry-point function, DriverProc, an audio device driver must have at least one of the following entry-point functions:

• wodMessage for waveform output drivers
• widMessage for waveform input drivers
• modMessage for MIDI output drivers and internal synthesizer drivers
• midMessage for MIDI input drivers
• auxMessage for auxiliary audio drivers
• msdMessage for mixer drivers

Drivers that service more than one type of audio device must have one of the above entry-point functions for each type of device serviced.These functions process messages sent by MMSYSTEM to the driver as the result of an application call to a low-level audio function. For example, when an application opens a waveform output device with the waveOutOpen function, MMSYSTEM sends the specified waveform output device driver a WODM_OPEN message. The driver's wodMessage function receives and processes this message.