Category: <b>DESQview/TopView and Quarterdeck programs</b>
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<pre><b>INT 15 - TopView - SEND MESSAGE - "LOCK" - REQUEST EXCLUSIVE ACCESS TO RESOURCE</b>

	AH = 12h
	BH = 14h
	BL = object
	    00h mailbox handle is DWORD on top of stack
	    02h use given task's mailbox (task's handle on top of stack)
	    03h use current task's default mailbox
Return: STACK popped if BL=00h
Note:	release exclusive access by sending CLOSE message to mailbox
	access may be requested multiple times, and requires multiple CLOSEs
SeeAlso: AH=12h/BH=0Dh
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