Re: Assign Reference to another Referance

From:

Paavo Helde <paavo@nospam.please.ee>

Newsgroups:

comp.lang.c++

Date:

Fri, 25 Sep 2009 00:06:07 -0500

Message-ID:

<Xns9C91526BC70D0nobodyebiee@216.196.109.131>

Paavo Helde <paavo@nospam.please.ee> kirjutas:

cpisz <cpisz@austin.rr.com> kirjutas:

On Sep 24, 4:37?pm, Paavo Helde <pa...@nospam.please.ee> wrote:

cpisz <cp...@austin.rr.com> kirjutas:

a reference around instead. Singletons have caused more

problems than

they are worth in the past, with release order in program

exit.

That's why singletons are often created dynamically and not
destroyed before program exit.

Paavo

I've never in all my reading seen a singleton pattern that did not
involve a global or static pointer, or reference, and thus involve
problems of dependency at program exit time when these are released.
Could you share this pattern that side steps the problem?

See eg.

http://groups.google.com/group/comp.lang.c++/browse_thread/thread/bca40

f40befc6a

Basically this comes down to:

class Singleton {
public:
         static Singleton& Instance();
         // ...
};

Singleton& Singleton::Instance() {
     static Singleton* the_singleton = new Singleton();
     return *singleton;
}

The static pointer is released at program exit,

Just a clarificition - this release is a non-op as pointer does not have
any destructor, meaning that the pointer retains its value regardless of
whether the runtime considers the statics in this compilation unit
released or not. So the singleton effectively remains operative also
later.

but the singleton itself
is never destroyed and remains intact until process exit.

Paavo