Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!bloom-beacon!mit-eddie!uw-beaver!uw-june!uw-entropy!dataio!pilchuck!ssc!happym!kent
From: kent@happym.UUCP (Kent Forschmiedt)
Newsgroups: comp.sources.d
Subject: Re: Simulation of 'alloca' -- can it be done in TurboC or MSC?
Keywords: alloca
Message-ID: <443@happym.UUCP>
Date: 25 May 88 23:14:58 GMT
References: <203@lcuxa.UUCP>
Reply-To: kent@happym.UUCP (Kent Forschmiedt)
Organization: Happy Man Corp.
Lines: 13

I don't know about TurboC, but MSC seems to use a conventional stack 
structure.  The alloca() that I use actually uses malloc() and 
free(), but saves a tag pointing to the current stack frame whenever 
a block is alloca()'d.  When alloca() is called, it free()'s all of 
the blocks whose tags point below (on a down-growing stack) the 
current frame.  I think that this scheme will work with any 
implementation that uses a real stack, but probably not if frames 
are randomly allocated from a heap, and I doubt that TurboC uses 
such an unconventional scheme. 
-- 
--
	Kent Forschmiedt -- kent@happym.UUCP, tikal!camco!happym!kent
	Happy Man Corporation  206-282-9598