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From: bzs@bu-cs.UUCP (Barry Shein)
Newsgroups: net.lang.c
Subject: Re: Re: questions from using lint
Message-ID: <667@bu-cs.UUCP>
Date: Sun, 25-May-86 15:07:48 EDT
Article-I.D.: bu-cs.667
Posted: Sun May 25 15:07:48 1986
Date-Received: Tue, 27-May-86 06:33:48 EDT
Organization: Boston Univ Comp. Sci.
Lines: 31


Re: User wants interactive, interpreted environment for C development

I believe the product SAFE/C from Catalytix Corp (Cambridge, MA?) provides
this. I have never used it but from what I have read and heard (a friend
was one of the developers) that is the basic idea of the product. If someone
has used this product I would be interested in your impressions. It is
available on a variety of machines and I believe is meant to be portable
but the marketing interest would probably have to be there, I dunno, ask em.

I think the main problem I would expect from such a product would be the
memory model. I suspect that memory management errors (eg. over-running
a malloc()'d area) could be hard to detect within the interpreted
environment unless carefully and specifically checked for (in which
case, what if I *want* to do some sort of overlaying/equivalencing.)

The point is (forgive me) that in the interpreted environment things
would point around differently than in the final compiled environment.
This is one reason why the lack of explicit pointers in LISP is a good
thing (I know, most lisps can allow an internals person to do an (addr x),
but it is highly disrecommended for several reasons in a program.)

I remember speaking about this with my friend when he was developing
and, although he agreed that yes indeed, that's a problem, they had
some compromise (I forget, maybe something like enabling/disabling
intensive checking with lintish /*SCREWMEM*/ statements, or maybe
that's just what they were considering at the time, this goes back
a coupla-few years.) I believe one of the main goals of the product
was to provide extensive run-time checking during development/testing.

	-Barry Shein, Boston University