Function 68h            Commit File                                  DOS 3.3+

    Flushes all stored (buffered) data for a file without closing the
    file; this ensures that the contents of the file are current.

        Entry   AH = 68h
                BX = File handle

        Return  AX = Error code, if CF is set
                     | 06h Invalid handle
                     | ??

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    This function provides a more efficient way to update file
    contents than closing a file and immediately reopening it.
    However, if a program opens or creates a file by specifying the
    flag open_flags_commit (4000h) with function 6ch (Extended Open/
    Create), the system updates the file each time the file is written
    to.