Re: Is this safe?

From:
Joshua Maurice <joshuamaurice@gmail.com>
Newsgroups:
comp.lang.c++.moderated
Date:
Mon, 6 Jul 2009 16:36:49 CST
Message-ID:
<efaddab1-dbe7-4550-9bd0-d2e8b364627a@2g2000prl.googlegroups.com>
On Jul 5, 10:51 pm, "Chris M. Thomasson" <n...@spam.invalid> wrote:

"Joshua Maurice" <joshuamaur...@gmail.com> wrote in message

news:c9d25c4c-da1b-4eab-b8e7-780fa7c401c6@k13g2000prh.googlegroups.com...
[...]

template <typename singleton_type>
void initialize_singleton()
{ singleton_type * & pointer =
singleton_wrapper_private_impl::get_pointer<singleton_type>();
    pointer = new singleton_type;
}

template <typename singleton_type>
singleton_type & singleton_wrapper()
{ //PTHREAD_ONCE_INIT presumably is a const expr,
    //and thus C++03 guarantees this happens before runtime.
    static pthread_once_t init_flag = PTHREAD_ONCE_INIT;

    int x =
        pthread_once(
            &init_flag,
            &initialize_singleton<singleton_type>
    );
    assert(0 == x);
    return *
singleton_wrapper_private_impl::get_pointer<singleton_type>();
}


You have undefined behavior; `initialize_singleton()' needs to be extern
"C".


Indeed. I believe I stated that in my post.

Also, to reduce confusion, my posts were posted here out of order of
when I submitted them, by several days. I wrote and submitted
On Jul 5, 1:48 am, Joshua Maurice <joshuamaur...@gmail.com>
before I wrote and submitted
On Jul 3, 9:09 am, Joshua Maurice <joshuamaur...@gmail.com>

Specifically, yes you can have multiple definitions of static data
members of class templates and not violate the One Definition Rule.

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