Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!uwm.edu!gem.mps.ohio-state.edu!ginosko!aplcen!haven!adm!smoke!gwyn
From: gwyn@smoke.BRL.MIL (Doug Gwyn)
Newsgroups: comp.lang.c
Subject: Re: The free() thing and function names
Message-ID: <11073@smoke.BRL.MIL>
Date: 15 Sep 89 11:58:49 GMT
References: <1989Sep14.022055.5961@twwells.com> <841@uniol.UUCP>
Reply-To: gwyn@brl.arpa (Doug Gwyn)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 26

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.  If you provide your
own external function named free(), you can break the implementation.

>What does the standard say about standardized function overriding ?

A program that does that is not strictly conforming.

>Maybe one have to distingish between
>   a.) C-Compiler: just the C keywords are reserved,
>       function overriding possible and possible more.
>   b.) C-System (C-Compiler plus standardized function package [often
>       called 'library']: C keywords reserved; return type, argument types
>       of standardized functions reserved; and more.

The Standard provides for two forms of conforming implementation:
"hosted" (for which the standard headers and standard library are
provided), and "free-standing" (which provides only minimal header
and library support).