This structure contains fields for the MCI_BUFFER message. It is used for both the mixWrite and mixRead entry points. In addition, when the mixer calls the application back, it will use an MCI_MIX_BUFFER pointer.
typedef struct _MCI_MIX_BUFFER { ULONG ulStructLength; /* Structure length. */ PVOID pBuffer; /* Pointer to a buffer. */ ULONG ulBufferLength; /* Length of the buffer. */ ULONG ulFlags; /* Flags. */ ULONG ulUserParm; /* User parameter. */ ULONG ulTime; /* Device time in ms. */ ULONG ulReserved1; /* Reserved. */ ULONG ulReserved2; /* Reserved. */ } MCI_MIX_BUFFER; typedef MCI _ MIX _ BUFFER * PMCI _ MIX _ BUFFER ;