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From: mikeb@inset.UUCP (Mike Banahan)
Newsgroups: net.lang.c
Subject: Re: Forward Referencing of Static Variables OK?
Message-ID: <717@inset.UUCP>
Date: Tue, 8-Oct-85 06:14:43 EDT
Article-I.D.: inset.717
Posted: Tue Oct  8 06:14:43 1985
Date-Received: Fri, 11-Oct-85 08:36:37 EDT
References: <365@tekcbi.UUCP>
Reply-To: mikeb@inset.UUCP (Mike Banahan)
Organization: The Instruction Set Ltd., London, UK.
Lines: 42
Xpath: stc stc-a

The orginal article asked what should happen in this sort of case:

/***********************************/
extern int xxx;

f(){
	xxx = 1;
}

static int xxx;	/* `extra' information about xxx */
/***********************************/

The ANSI committee had a lot of work to do on this one.
There is an even worse issue than that:

/***********************************/
f(){
	{
	extern int xxx;	/* OH BOY!!! - where am I visible? */
			/* Am I really extern? */
	}
}

y(){
	/* can I use xxx in here ???? */
}
/***********************************/

They had to come up with a lot of words to fix that stuff - basically, it
just wan't written down anywhere what was supposed to happen. Bill Plauger
described the whole mess as ``Driving a coach and horses through block
structure.'' The more I look at it, the more I agree.

X3J11 has come up with a set of answers on what should happen. Because
nobody really ``knew'' before, you just get what your compiler happens to
give you. Be warned - it is *highly* nonportable practice, because
different compilers currently do different things. This is one area
where the language was already broken. The standard has chosen one way
of patching it.
-- 
Mike Banahan, Technical Director, The Instruction Set Ltd.
mcvax!ukc!inset!mikeb