This structure contains fields for the SHC_SENDMSG message.
typedef struct _PARM_SNDMSG {
ULONG ulFunction; /* Handler command function. */
HID hid; /* Handler ID. */
HSTREAM hstream; /* Handle of stream instance. */
ULONG ulMsgType; /* Stream handler message type. */
PVOID pMsg; /* Pointer to message control block. */
} PARM_SNDMSG;
typedef PARM _ SNDMSG FAR * PPARM _ SNDMSG ;