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From: drw@cullvax.UUCP (Dale Worley)
Newsgroups: comp.lang.c
Subject: Question on external struct declarations in ANSI C
Message-ID: <1429@cullvax.UUCP>
Date: Tue, 4-Aug-87 10:52:16 EDT
Article-I.D.: cullvax.1429
Posted: Tue Aug  4 10:52:16 1987
Date-Received: Thu, 6-Aug-87 01:53:37 EDT
Organization: Cullinet Software, Westwood, MA, USA
Lines: 22

arnold@emory.uucp (Arnold D. Robbins {EUCC}) writes:
> Well, the kernel header files are full of declarations like
> 
> 	extern struct pte Mbmap[];		/* page tables to map mbutl */
> 
> where, e.g., what a 'struct pte' is has not been previously defined. /bin/cc
> lets you do this, and does not complain until you try to actually use one of
> these things or a member of one. GNU CC, on the other hand, promptly dies
> miserably when it sees such a declaration. GNU CC claims to follow the rules
> of (a version of) the draft standard.

Well, reading 3.5.2.2 and 3.5.3.2 of the draft suggests that this
module doesn't need to know the size of Mbmap at all (unless you
sizeof it or something), and so the size of struct pte doesn't need to
be known, and so struct pte need not be fully declared.

Dale

-- 
Dale Worley	Cullinet Software		ARPA: cullvax!drw@eddie.mit.edu
UUCP: ...!seismo!harvard!mit-eddie!cullvax!drw
OS/2: Yesterday's software tomorrow