Int 21 Fn 68  - DOS 3.3+ - "fflush" - Commit File                          [D]

   AH = 68h
   BX = file handle

Return: CF clear if successful
       all data still in DOS disk buffers is written to disk immediately,
         and the file's directory entry is updated
   CF set on error
       AX = error code (see AH=59h)

See Also: AX=5D01h,AH=6Ah,INT 2F/AX=1107h