This function descends into a chunk beginning at the current file position, or searches for a specified chunk.

#define INCL_MMIOOS2
#include <os2.h>

HMMIO        hmmio;          /*  Open file handle. */
PMMCKINFO    pckinfo;        /*  Pointer to MMCKINFO. */
PMMCKINFO    pckinfoParent;  /*  Pointer to MMCKINFO. */
USHORT       usFlags;        /*  Flags. */
USHORT       rc;             /*  Return codes. */

rc = mmioDescend(hmmio, pckinfo, pckinfoParent,
       usFlags);