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Path: utzoo!mnetor!seismo!husc6!necntc!ima!haddock!karl
From: karl@haddock.UUCP (Karl Heuer)
Newsgroups: comp.lang.c
Subject: Re: Local string storage -- *guaranteed* static?
Message-ID: <512@haddock.UUCP>
Date: Wed, 3-Jun-87 22:33:54 EDT
Article-I.D.: haddock.512
Posted: Wed Jun  3 22:33:54 1987
Date-Received: Sun, 7-Jun-87 05:38:17 EDT
References: <7690@brl-adm.ARPA>
Reply-To: karl@haddock.ISC.COM.UUCP (Karl Heuer)
Organization: Interactive Systems, Boston
Lines: 25

In article <7690@brl-adm.ARPA> gea@Juliet.Caltech.EDU (Gary Ansok) writes:
>Someone asked whether strings in functions like
>    func() { char *str = "some string"; ... return(str); }
>are static, and several people affirmed that they were, but without any
>evidence.  ... But is there any guarantee, either in K&R or in the Draft
>Standard, that this data will be static?

Yes.  K&R, Appendix A, 2.5 (p. 181): "A string has ... storage class static";
dpANS May86, 3.1.4 (String Literals): "Semantics  A string literal has static
storage duration ...".

>By the way, the question can be avioded if the function is re-written as:
>    func() { static char str[] = "some string"; ... return(str); }

Actually, if you want identical semantics, you'd want
    func() { static char b[]="some string"; char *str=b; ... return(str); }
although you do get the same results if str is otherwise unused -- in which
case you might as well simplify to
    func() { ... return ("some string"); }

>Moral:  Don't make assumptions when you can tell the compiler what you mean.

Moral: RTFM, then assume that what it says is true.

Karl W. Z. Heuer (ima!haddock!karl or karl@haddock.isc.com), The Walking Lint