Subj : Re: Boost.Threads on its way to C++0x
To   : comp.programming.threads
From : Peter Dimov
Date : Tue Apr 26 2005 07:57 pm

gottlobfrege@gmail.com wrote:
> Peter Dimov wrote:
>> gottlobfrege@gmail.com wrote:
>>> - a static_local template:
>>>
>>> int func()
>>> {
>>>   // this thread-safely inits foo only once
>>>   static static_local<Foo> foo(foo_param1, foo_param2,...);
>>
>> How do you solve the race condition WRT the hidden compiler-
> > generated boolean flag?
>
> There are lots of ways, but they all boil down to the same thing: ie
> you ignore the compiler's flag and use your own.  And use call_once to
> set your flag.

Isn't this the usual broken DCL?

int func()
{
    if( !__flag )
    {
        call constructor
            lock
                do things
            unlock
        __flag = true;
    }
}

What prevents __flag = true migrating upwards above "do things"?

.