Newsgroups: comp.lang.c++
Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!ispd-newsserver!tuna!randolph
From: randolph@tuna.ssd.kodak.com (Gary L. Randolph)
Subject: Re: Static member definition vs. declaration?
Message-ID: <1991May8.120340.176@ssd.kodak.com>
Sender: news@ssd.kodak.com
Organization: Eastman Kodak
References: <1991Apr19.133728.5300@clear.com> <1991Apr30.195846.16760@ccad.uiowa.edu> <72218@microsoft.UUCP>
Date: Wed, 8 May 91 12:03:40 GMT

In article <72218@microsoft.UUCP> jimad@microsoft.UUCP (Jim ADCOCK) writes:
>|We have a debate in our group.  When you declare a static
>|member, such as:
>|
>|   class X {static int myVar;};
>|
>|Do you need to make a definition elsewhere,
>|
>|   int X::myVar;
>|
>
>In C++ static members are only allowed for global classes.  The mention of such
>inside of the class is only a declaration, the actual definition must
>occur at file scope.
>
>Some C++ compilers allow declaration without such explicit definition.
>This is a *compiler* anachronism as listed in section 18.3 of ARM, not part
>of the C++ *language* as defined today.

What Jim says is certainly true. I have an additional comment and a suggestion
that you obviously may ignore.

comment:

One point that may be news to at least the novice C++er is that static members
have external linkage.  This is not what C programmers are used to.  In fact
many programmers believe that static MEANS private and permanent. Usually it 
does.  This is an exception.

suggestion:

As Jim implies, you should never rely on a compiler allowing you to forego the
definition. 

Gary