This function writes the I/O buffer of a file to disk, if the I/O buffer was written into. It also empties the buffer if requested.

#define INCL_MMIOOS2
#include <os2.h>

HMMIO     hmmio;    /*  Open file handle. */
USHORT    usFlags;  /*  Flags. */
USHORT    rc;       /*  Return codes. */

rc = mmioFlush(hmmio, usFlags);