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From: karl@haddock.ima.isc.com (Karl Heuer)
Newsgroups: comp.lang.c
Subject: Re: Difference between "char *arr" and "char arr[]"
Message-ID: <18183@haddock.ima.isc.com>
Date: 25 Sep 90 03:36:44 GMT
References: <8103@aggie.ucdavis.edu> <ENAG.90Sep23231057@hild.ifi.uio.no> <26680@mimsy.umd.edu> <ENAG.90Sep25005953@hild.ifi.uio.no>
Reply-To: karl@kelp.ima.isc.com (Karl Heuer)
Organization: Interactive Systems, Cambridge, MA 02138-5302
Lines: 16

In article <ENAG.90Sep25005953@hild.ifi.uio.no> enag@ifi.uio.no (Erik Naggum) writes:
>Rather, "char arr[14]" declares an array, but "extern char arr[]" only
>declares that "arr" is some constant pointer the value of which is to
>be resolved by the linker.

I disagree.  Both are *declarations*; the one without "extern" happens to also
serve as a *definition*.  So I would say that "char arr[14]" declares an array
and (being a definition) also causes storage to be allocated for it (probably
by a linker), while "extern char arr[]" declares an array and causes the name
"arr" to be associated with the same storage that was allocated under that
name in some other compilation unit.

There are no pointers (in the C sense) involved here, at least not until such
time as the name "arr" is used in an rvalue context.

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