The return values for the low-order word of DriverProc are listed in the function and message reference for MCI commands included with the Microsoft Windows Software Development Kit. General error returns are listed with the mciSendCommand function. Error returns specific to opening a device are listed with the MCI_OPEN message. (The error returns listed with mciSendString are returned by MCI; your device driver does not need to return them.)
The return values for the low-order word of DriverProc are listed in the function and message reference for MCI commands included with the Microsoft Windows Software Development Kit. General error returns are listed with the mciSendCommand function. Error returns specific to opening a device are listed with the MCI_OPEN message, later in this chapter. (The error returns listed in the SDK as being specific to mciSendString are returned by MCI; your device driver does not need to return them.)
The high-order word of DriverProc return value is used by mciSendString to translate information returned in structure used with lParam2. For information on the contents of the high-order word of the DriverProc return value, see Returning Information in an MCI Structure.