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From: keesan@cc5.bbn.com.UUCP
Newsgroups: comp.lang.c
Subject: Re: static variables
Message-ID: <1546@cc5.bbn.com.BBN.COM>
Date: Thu, 4-Jun-87 16:15:31 EDT
Article-I.D.: cc5.1546
Posted: Thu Jun  4 16:15:31 1987
Date-Received: Sat, 6-Jun-87 07:05:48 EDT
References: <7653@brl-adm.ARPA> <4064@amd.UUCP> <183@inco.UUCP>
Reply-To: keesan@cc5.bbn.com.UUCP (Morris M. Keesan)
Organization: Bolt Beranek and Newman, Cambridge, MA
Lines: 36
Summary: variable is automatic, string is static

In article <183@inco.UUCP> mack@inco.UUCP (Dave Mack) writes:
>In article <4064@amd.UUCP>, markg@amd.UUCP (Mark Gorlinsky) writes:
>> In article <7653@brl-adm.ARPA> jfjr@mitre-bedford.arpa writes:
>> >Are character strings local to a function static??
>> Yes!!!!!!!!!
>I disagree. A static variable retains its value between function
>calls, while an initialized local variable is reinitialized on
>each call to the function. Try this code to see what I mean:
>#include <stdio.h>
>main()
>{
>	out();
>	out();
>}
>out()
>{
>	char *s = "Hello";
>	static char *s2 = "World!";
>	printf("%s %s\n",s,s2);
>	s = "Goodbye";
>	s2 = "Mom";
>}

Basic confusion here.  s and s2 are automatic variables, "Hello", "World!",
"Goodbye", and "Mom" are static strings. (Ref: K&R p. 193, sec. 8.1; p. 181,
sec. 2.5).  Instead s = "Goodbye" and s2 = "Mom" in the above, try

s[0] = 'J';
s2[0] = 'M'; s2[2] = 'l';

In the original example, { char *some_string = "some string"; }, some_string
is automatic and "some string" is static.
-- 
Morris M. Keesan
keesan@bbn.com
{harvard,decvax,ihnp4,etc.}!bbn!keesan