Article View: comp.lang.c.moderated
Article #2199Behaviour of mem functions when n=0 ?
From: Lawrence Kirby
Date: Thu, 07 Mar 1996 00:28
Date: Thu, 07 Mar 1996 00:28
34 lines
2074 bytes
2074 bytes
In article <4hgc3d$97a@solutions.solon.com>
larry.jones@sdrc.com "Larry Jones" writes:
> In article <4hdqn5$8qn@solutions.solon.com>, fred@genesis.demon.co.uk
> (Lawrence Kirby) writes about memcmp et al. with n==0:
> > Probably. However the result is defined by some rather unfortunate wording in
> > the standard:
>
> The intent of the standard has been clarified by a Technical Corrigendum
> which adds the following text to the introductory matter in 7.11.1
> String Function Conventions:
>
> Where an argument declared as |size_t n| specifies the length of
> the array for a function, |n| can have the value zero on a call
> to that function. Unless explicitly stated otherwise in the
> description of a particular function in this subclause, pointer
> arguments on such a call must still have valid values, as
> described in subclause 7.1.7. On such a call, a function that
> locates a character finds no occurrence, a function that
> compares two character sequences returns zero, and a function
> that copies characters copies zero characters.
>
> Note that this applies to the strn* functions as well as the mem*
> functions.
That does pretty much clear it up. However the wording for the individual
functions is still nonsensical and it would have been better if that had
been fixed.
--
-----------------------------------------
Lawrence Kirby | fred@genesis.demon.co.uk
Wilts, England | 70734.126@compuserve.com
-----------------------------------------
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Path: arc1-ca.pugleaf.net!solon.com!not-for-mail From: fred@genesis.demon.co.uk (Lawrence Kirby) Newsgroups: comp.lang.c.moderated,comp.std.c Subject: Behaviour of mem functions when n=0 ? Date: 6 Mar 1996 18:28:45 -0600 Organization: none Sender: clc@solutions.solon.com Approved: clc@solutions.solon.com Message-ID: <4hlaju$4g0@solutions.solon.com> Reply-To: fred@genesis.demon.co.uk NNTP-Posting-Host: solutions.solon.com X-Mailer: Demon Internet Simple News v1.27