www.delorie.com/djgpp/doc/rbinter/30.html   search  
2158

Category: DOS kernel

INT 21 - DOS 5+ - GET OR SET UMB LINK STATE

	AH = 58h
	AL = subfunction
	    02h get UMB link state
		Return: AL = current link state
			    00h UMBs not part of DOS memory chain
			    01h UMBs in DOS memory chain
	    03h set UMB link state
		BX = new link state
		    0000h remove UMBs from DOS memory chain
		    0001h add UMBs to DOS memory chain
Return: CF clear if successful
	CF set on error
	    AX = error code (01h) (see #01680)
Notes:	a program which changes the UMB link state should restore it before
	  terminating
	UMBs will only be available if CONFIG.SYS contains the line DOS=UMB,
	  the UMBs have been linked into the memory chain with AX=5803h, and
	  the allocation strategy has been set to include high memory with
	  AX=5801h
SeeAlso: #01687,#02766 at INT 2F/AX=4310h

  webmaster   donations   bookstore     delorie software   privacy  
  Copyright 2000   by Ralf Brown     Updated Jul 2000