The following code illustrates how to modify information in a file.

   HMMCF hmmcf1;
   MMCFINFO &mmcfinfo;
   ULONG cBytes;
   ULONG rc;
    ...

   memset(&mmcfinfo, '\0', sizeof(MMCFINFO));
   rc = mmioCFGetInfo( hmmcf1, &mmcfinfo, (ULONG)sizeof(ULONG));
   if (rc != (ULONG)sizeof(ULONG))
      break;
   else
      cBytes = pmmcfinfo->ulHeaderSize;
    ...

   rc = mmioCFSetInfo( hmmcf1, &mmcfinfo, cBytes);
   if (rc)
     /* error */
   else
    ...