HelpPC 2.10 Quick Reference Utility Copyright 1991 David Jurgens

      INT 15,20 - PRINT.COM Critical Region Flag (undocumented DOS 3.x+)

       AH = 20h
       AL = 00  disable user critical region flag
          = 01  enable user critical region flag
       ES:BX = pointer to user critical region flag byte (AH = 1)


       returns nothing


       - provides PRINT.COM with the address of a byte to increment on
         entry to DOS functions
       - see bibliography reference for "Undocumented DOS"

Esc or Alt-X to exit int 15,20 Home/PgUp/PgDn/End ←↑↓→