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From: mwm@pa.dec.com (Mike (My Watch Has Windows) Meyer)
Subject: Re: Any restrictions with making programs PURE?
In-Reply-To: crazyrat@disk.uucp's message of 19 Apr 91 23:11:19 GMT
Message-ID: <MWM.91Apr23124114@raven.pa.dec.com>
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Organization: Missionaria Phonibalonica
References: <1991Apr12.203658.11790@unlinfo.unl.edu>
	<1991Apr19.231119.6428@disk.uucp>
Date: 23 Apr 91 12:41:14
Lines: 27

In article <1991Apr19.231119.6428@disk.uucp> crazyrat@disk.uucp (@jap) writes:
   In article <1991Apr12.203658.11790@unlinfo.unl.edu>, 231b3678@fergvax.unl.edu (Phil Dietz) writes:
   > Are there any restrictions with making 'C' programs PURE?  Is it just a matter
   > of linking it with cres.o?

   From my experience, the only way a program can be pure is to make the code
   re-entrant.  That is, all variable space has been DYNAMICALLY allocated.

This is correct.

   I don't normally do re-entrant routines in C, but in Assembler.  It's much
   easier..

This isn't. Linking with cres.o is enough to get the C compiler to
dynamically allocate your statics. That takes care of that. If you
need to refer to an absolute object (Custom comes to mind) you'll have
to declare it far. I vaguelly recall some compilation modes that don't
work with cres.o (-b0?), but don't have the details in handy.

	<mike


--
The sun is shining slowly.				Mike Meyer
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