| MIDM_ADDBUFFER | Adds a buffer to the input queue. |
| MIDM_CLOSE | Closes and deallocates a MIDI input device. |
| MIDM_GETDEVCAPS | Requests the capabilities of a MIDI input device. |
| MIDM_GETNUMDEVS | Requests the number of MIDI input devices a driver supports. |
| MIDM_OPEN | Opens and allocates a MIDI input device. |
| MIDM_RESET | Stops output and returns all data blocks to the client application. |
| MIDM_START | Begins MIDI input and resets the time stamp to zero. |
| MIDM_STOP | Ends MIDI input. |