Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!uupsi!sunic!liuida!isy!lysator.liu.se!zap
From: zap@lysator.liu.se (Zap Andersson)
Newsgroups: comp.sys.amiga.programmer
Subject: Re: Is this valid C?
Message-ID: <616@lysator.liu.se>
Date: 6 May 91 08:57:38 GMT
References: <1991May5.222328.16225@csis.dit.csiro.au>
Sender: news@isy.liu.se (Lord of the News)
Organization: Lysator Computer Club, Linkoping University, Sweden
Lines: 57

dave@csis.dit.csiro.au (David Campbell) writes:

>Is this valid C?

>Its just that this will compile on my favourite Unix compiler but won't
>on Lattice V5.10.

>I wish G++ was around for the Amiga!!!!!!

>It turns out that C++ (on my Sparc) spits out similar code (I'm using
>C++ on the sun to develop programs for the Amiga).

>/*--------------------------------------------------------------------------*/
>extern struct thing t;

This is very invalid, since struct thing isn't defined yet. However the line
extern struct thing *t; 
is valid, even though 'thing' isn't defined yet.

>struct thing {
>	int n;
>	char *s;
>};


>main()
>{
>	t.n = 10;
>	t.s = "hello";
>}
>/*--------------------------------------------------------------------------*/

Question is how an access of the  t->n  and t->s would go, (if it
was defined as a pointer, in my case) now? I.e:
 
struct foop *p;

struct foop { int a; char *b };

main()
{
	p = malloc(...)
        p->a = 39;  /* Will complier barf here? Since the contents of
                       the structure 'foop' was defined AFTER the 'pointer
                       to unknown structure' p was created? Hmmmm? */
}

>-- Dave Campbell
>-- dave@csis.dit.csiro.au

>-- 
>dave campbell
--
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