Important Notice

The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.

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     After performing a final exit, MS-DOS takes the following actions:
 
        ■ All memory belonging to the process is released.
 
        ■ File buffers are flushed, and any open handles for files or
          devices owned by the process are closed.
 
        ■ The termination handler vector (Int 22h) is restored from
          PSP:000Ah.
 
        ■ The CTRL+C handler vector (Int 23h) is restored from
          PSP:000Eh.
 
        ■ The critical-error handler vector (Int 24h) is restored from
          PSP:0012h.
 
        ■ Control is transferred to the termination handler.
 
     If the program is returning to COMMAND.COM, control transfers to
     the resident portion, and the transient portion is reloaded if
     necessary. If a batch file is in progress, the next line of the
     file is fetched and interpreted; otherwise, a prompt is issued for
     the next user command.
 
     Any files that have been written to using FCBs should be closed
     before performing this exit call; otherwise, data may be lost.
 
     Other methods of performing a final exit are Int 20h, Int 21h
     Function 31h, Int 21h Function 4Ch, and Int 27h. Int 21h Functions
     31h and 4Ch are the preferred method for termination because they
     allow a return code to be passed to the parent process.
 
     [Version 3.0+]
     If the program is running on a network, it should remove all locks
     it has placed on file regions before terminating.
                                    -♦-