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From: alan@allegra.UUCP (Alan S. Driscoll)
Newsgroups: net.lang.c
Subject: Re: C compiler for pdp-11 under RSX
Message-ID: <2525@allegra.UUCP>
Date: Sat, 9-Jun-84 20:22:05 EDT
Article-I.D.: allegra.2525
Posted: Sat Jun  9 20:22:05 1984
Date-Received: Sun, 10-Jun-84 02:13:22 EDT
References: <1880@sdccsu3.UUCP>, <192@dicomed.UUCP> <2849@brl-vgr.ARPA>, <873@orca.UUCP>, <3946@utzoo.UUCP>
Organization: AT&T Bell Laboratories, Murray Hill
Lines: 22

> On many systems, the loader doesn't speak COMMON blocks and requires
> that a single module (file) EXPORT a symbol and that all other modules
> IMPORT it.  When compiling C code a file at a time, there is no way to
> do this with the existing language definition.

As Henry Spencer has already pointed out, the definition of C doesn't
require that unitialized data be made common, although many existing
compilers do this.  (I know, some sloppy code depends on it.)

To export a symbol, you say something like

	int foo;

To import it, you say

	extern int foo;

There really isn't any problem.
-- 

	Alan S. Driscoll
	AT&T Bell Laboratories