Re: New Singlton Scheme

From:

Maciej Sobczak <see.my.homepage@gmail.com>

Newsgroups:

comp.lang.c++.moderated

Date:

Wed, 29 Aug 2007 13:57:48 CST

Message-ID:

<1188392810.319195.274600@50g2000hsm.googlegroups.com>

On 29 Sie, 15:10, Dmitriy Vyukov <dvyu...@gmail.com> wrote:

Mayers singleton have following advantages and drawbacks:
+ created by first request

The advantage of this is that the object is *not* created if it's not
needed.

// some_service.h

/** Service interface
*/
struct some_service
{
    void make_something() {}

};

/** Service interface getter
*/
some_service& get_service();

// some_service.cpp

some_service& get_service()
{
    static some_service instance;
    return instance;

}

static some_service& local = some_service(); // <-----------------

^^^^^^^^^^^^^^

I guess it should be get_service() instead of some_service();

This approach does not have the advantage mentioned earlier.

The disadvantage here is that there is no way to pass run-time
parameters to the singleton constructor.

This implementation eliminate problems with multithreaded creation

The problem of multithreaded creation can be also eliminated by
instantiating the singleton before starting new threads in main.

--
Maciej Sobczak
http://www.msobczak.com/

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