The following code illustrates how to return the header of a file.

   HMMIO  hmmio1;
   PCHAR  pHeader;
   USHORT lHeaderLength;
   USHORT LONG lBytesRead;
   ULONG  ulReserved = 0L;
   ULONG  ulFlags = 0L;
   ULONG  rc;
    ...

   rc = mmioGetHeader( hmmio1,
                       pHeader,
                       lHeaderLength,
                       &lBytesRead,
                       ulReserved,
                       ulFlags);
   if (rc)
     /* error */
   else
    ...