This data structure contains fields for the DDCMD_READ and DDCMD_WRITE messages.
typedef struct _ddcmd_readwrite_parm {
ULONG ulFunction; /* Function requested by stream handler. */
HSTREAM hStream; /* Stream handle. */
PVOID pBuffer; /* Buffer pointer. */
ULONG ulBufferSize; /* Buffer size. */
PVOID pProcessLin; /* Process linear record pointer. */
BOOL fEOS; /* Whether or not this is the EOS buffer. */
ULONG ulParm1; /* Reserved for future use. */
ULONG ulParm2; /* Reserved for future use. */
ULONG ulLength; /* Length of the structure. */
} DDCMDREADWRITE;