Re: Accessing non-static class members fom static methods (About an alternative)

From:

Ulrich Eckhardt <eckhardt@satorlaser.com>

Newsgroups:

microsoft.public.vc.language

Date:

Thu, 24 Jul 2008 09:12:24 +0200

Message-ID:

<pjmll5-4k4.ln1@satorlaser.homedns.org>

K?r?at wrote:

We generally access non-static class members from a static method by
passing "this" to that static method and accessing non-static members over
"this".

Why make it static in the first place then? If you need an object as
context, make it a memberfunction.

My alternative is caching "this" into a static member and use that static
member whenever you need to access non-static members. Is there anything
bad about this solution?

Yes. If something belongs to an object, make it part of that object.
Secondly, you solution will fall apart when used in a multithreaded
environment. Generally, all arguments why globals are bad apply to this
case, too, except that the scope is a bit smaller than global.

class Foo
{
public:
    static Foo * lpThis;
    Foo ()
    {
        // Some initializations...
        lpThis = this; // Last statement in the constructor...
    }

    static void doJob ()
    {
        // Now we can access all non-static members over static
        "lpThis"...
    }
};
Foo * Foo::lpThis;

This looks like an attempt to create a so-called "singleton". Make a
websearch, there are much better ways to achieve the same. Not using a
singleton would be another alternative, too.

Uli

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