Path: utzoo!attcan!uunet!iconsys!bryan
From: bryan@iconsys (Bryan Cardoza)
Newsgroups: comp.lang.c
Subject: Re: external declarations of ptrs and arrays
Message-ID: <61@iconsys>
Date: 31 Jul 90 16:48:06 GMT
References: <674@dg.dg.com>
Organization: SANYO/ICON, Orem, Utah
Lines: 35

In article <674@dg.dg.com> hmelman@absolut.rtp.dg.com (Howard Melman) writes:
>I have the file declare.c:
>
>char temp[20]="blah";
>
>I have the file use.c:
...
>extern char *temp;
...
>This causes a core dump.  When I change my extern declaration in use.c to be:
>
>extern char temp[];
>
>the program works fine.  I was under the impression that the two
>declarations were the same.  Help...

No so.  When using *temp, the contents of temp are used, whereas
when using temp[], the address of temp is used.  In M68k assembly
(using the System V/68 assembler syntax) we are talking about the
difference between

	mov.l	temp,%a0

for *temp and

	mov.l	&temp,%a0

for temp[].  Sure, you can often use the two the same way in your
C programs, but remember, we're talking about a storage declaration
here, and pointers and arrays are not the same thing.
-- 
Bryan Cardoza			UUCP: uunet!iconsys!bryan
Software Engineer		Internet: bryan@iconsys.icon.com
Icon International, Inc.	(801) 225-6888
Orem, Utah			FAX: (801) 226-0651