The following code illustrates how to write to a file.

   HMMIO hmmio1;
   PCHAR pchBuffer;
   LONG  cBytes;
   LONG  lBytesWritten;
    ...

   lBytesWritten = mmioWrite(hmmio1, pchBuffer, cBytes);

   if (lBytesWritten < 0L)
     /* error */
   else
    ...