Category: <b>DESQview/TopView and Quarterdeck programs</b>
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<pre><b>INT 15 - DESQview v2.26+ - "ASSERTVIR" - CONTROL 386 SCREEN VIRTUALIZATION</b>

	AX = DE21h
	BX = new state
	    0000h turn off
	    nonzero turn on
Return: BX = old state of virtualization
Notes:	this API call may be made from within a hardware interrupt handler
	under DV 2.40 and 2.42, this call appears to have no effect and always
	  returns a nonzero value in BX which appears to be the offset within
	  the DV common memory segment of the caller's task object; it may
	  only have an effect within a hardware interrupt handler
SeeAlso: AX=1117h,AX=DE17h
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