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 ;