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From: richard@aiai.ed.ac.uk (Richard Tobin)
Newsgroups: comp.lang.c
Subject: Re: The free() thing and function names
Message-ID: <902@skye.ed.ac.uk>
Date: 19 Sep 89 15:26:17 GMT
References: <1989Sep14.022055.5961@twwells.com> <841@uniol.UUCP> <11073@smoke.BRL.MIL>
Reply-To: richard@aiai.UUCP (Richard Tobin)
Organization: AIAI, University of Edinburgh, Scotland
Lines: 30

In article <11073@smoke.BRL.MIL> gwyn@brl.arpa (Doug Gwyn) writes:
>In article <841@uniol.UUCP> lehners@uniol.UUCP (Joerg Lehners) writes:
>>Don't hardcode any (even standard) functions into the compiler.
>>What about writing my own free() function, possibly with a completly
>>different semantic ?
>
>You absolutely must NOT do that in a hosted implementation.  Several
>library routines may depend, not only on the documented semantics of
>an external function named free(), but also on implementation-specific
>internal properties of the free() implementation.  

This is a real pain for programs (like interpreters for other languages)
that need to keep track of just what memory is in use.  A helpful
implementation would at least provide a way of producing code that
relied only on the advertised semantics of malloc(), etc, perhaps by
means of a compiler flag.

[Incidentally, if Joerg Lehners really wants "completely different"
semantics for free - rather than just say keeping a note of whats been
freed in addition to freeing the block - then he's going to lose!]

I hope that this will be treated as a "quality of implementation"
issue.

-- Richard

-- 
Richard Tobin,                       JANET: R.Tobin@uk.ac.ed             
AI Applications Institute,           ARPA:  R.Tobin%uk.ac.ed@nsfnet-relay.ac.uk
Edinburgh University.                UUCP:  ...!ukc!ed.ac.uk!R.Tobin