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From: cok@islsun.Kodak.COM (David Cok)
Newsgroups: comp.std.c++
Subject: Re: type/member tags
Message-ID: <1991Mar12.123811.13701@kodak.kodak.com>
Date: 12 Mar 91 12:38:11 GMT
References: <1399@culhua.prg.ox.ac.uk> <27D3E544.619A@tct.uucp> <4338@lupine.NCD.COM>
Sender: cok@Kodak.COM
Organization: Eastman Kodak Co., Rochester, NY
Lines: 31

In article <4338@lupine.NCD.COM> rfg@NCD.COM (Ron Guilmette) writes:
>In article <27D3E544.619A@tct.uucp> chip@tct.uucp (Chip Salzenberg) writes:
>+According to bill@robots.oxford.ac.uk (Bill Triggs):
>+>Creation of an instance of an implicitly specified class....
>+>It seems that an appropriately global `class-designator' is
>+>indispensable for this, whether string or global address or
>+>global enumeration constant ...
>+
>+The class name is already guaranteed to be unique (name equivalence
>+and all that).  What need of more?
>
>Not only are file-scope class names not guaranteed to be unique across
>multiple independent compilation units (which may later be combined to
>form a single program) but class names need not even be unique *within*
>a single compilation unit.  (Remember that any given compilation unit may
>contain numerous independent declarative scopes.)
>-- 

I agree that class names can be reused in local scopes within functions and
other classes.   But can they be reused at file scope in different 
compilation units?  I thought these were effectively global, as free
functions are.  If you try this with Sun C++ (and the classes happen to
have non-inline functions with the same name and parameter types) you
will get a link error with a multiply defined function error.  Not to
necessarily advocate the use of a class name as a type tag, but it seems
that it would work, with suitable mangling for local scopes, if one
wanted to do it.

David R. Cok
Eastman Kodak Co.
cok@Kodak.COM