Interrupt 20h DOS - Terminate Program (obsolete, see Int\21f\4C) entry no parameters return The following vectors are restored from the Program Segment Prefix: 0Ah Program Terminate 0Eh Control-C 12h Critical Error note Officially frowned upon since the introduction of DOS 2.0 This vector transfers to the logic in DOS to restore the terminate address, the Ctrl-Break address, and the critical error exit address to the values they had on entry to the program. All the file buffers are flushed and all handles are closed. You should close all files changed in length (see Int\21f\10 and Int\21f\3E) before issuing this interrupt. If the changed file is not closed, its length, time, and date are not recorded correctly in the directory. For a program to pass a completion code or an error code when terminating, it must use either Int\21f\4C (Terminate a Process) or Int\21f\31 (Terminate Process and Stay Resident). These two methods are preferred over using int 20h and the codes returned by them can be interrogated in batch processing. Important: Before you issue an interrupt 20h, your program must ensure that the CS register contains the segment of its program segment prefix. (see Int\27 -CS must point)