The MMIO Manager uses the MMCFINFO data structure to maintain state information on an open file. The MMCFINFO data structure is defined in the MMIOOS2.H header file as shown.
typedef struct _MMCFINFO /* mmcfinfo */
{
ULONG ulHeaderSize; /* CTOC header size */
ULONG ulEntriesTotal; /* Num of CTOC table entries */
ULONG ulEntriesDeleted; /* Num of CTOC table entries to deleted CGRP */
ULONG ulEntriesUnused; /* Num of unused CTOC entries */
ULONG ulBytesTotal; /* Combined byte size of all CGRP elements */
ULONG ulBytesDeleted; /* Byte size of all deleted CGRP elements */
ULONG ulHeaderFlags; /* Information about entire compound file (CF) */
USHORT usEntrySize; /* Size of each CTOC table entry */
USHORT usNameSize; /* Size of name field in entry, default 13 */
USHORT usExHdrFields; /* Num CTOC header extra fields */
USHORT usExEntFields; /* Num CTOC entry extra fields */
} MMCFINFO;