For a description of handling the error return values from DriverProc for system messages, see the description of installable device drivers in the Microsoft Windows Software Development Kit. The following table summarizes the error codes defined for joystick drivers:
| Error code | Definition |
|---|---|
| MMSYSERR_NOERROR | No error. |
| MMSYSERR_NODRIVER | No joystick device driver is present. |
| JOYERR_PARMS | Invalid parameters were passed with the message. |
| JOYERR_NOCANDO | Driver cannot perform the requested task because some service is unavailable. |
| JOYERR_UNPLUGGED | Specified joystick is unplugged. |