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Path: utzoo!henry
From: henry@utzoo.UUCP (Henry Spencer)
Newsgroups: comp.lang.c
Subject: Re: Scope of externals definitions
Message-ID: <8652@utzoo.UUCP>
Date: Thu, 24-Sep-87 13:27:56 EDT
Article-I.D.: utzoo.8652
Posted: Thu Sep 24 13:27:56 1987
Date-Received: Thu, 24-Sep-87 13:27:56 EDT
References: <8959@auspyr.UUCP>
Organization: U of Toronto Zoology
Lines: 20

Since nobody else has taken this one on...

>	The scope of an external variable lasts from the point at which it
>	is declared in a source file to the end of that file. ...

Historically, the old C compilers took an "extern" declaration to be global
even if it appeared inside a function.  X3J11 (1 Oct 1986 draft) says that
this is not the case, that the scope of an identifier declared within a
function is the function body.  (Roughly speaking.)  The old behavior is
mentioned in the appendix as a "common extension".

>	The lexical scope of identifiers declared in external definitions
>	persists from the definition through the end of the source file
>	in which they appear.

This one isn't relevant, because "external definition" in K&Rspeak is a
magic phrase with a specific meaning that doesn't apply here.
-- 
"There's a lot more to do in space   |  Henry Spencer @ U of Toronto Zoology
than sending people to Mars." --Bova | {allegra,ihnp4,decvax,utai}!utzoo!henry