Subj : Re: Can C++ local static objects be made thread safe?
To   : comp.programming.threads
From : Gianni Mariani
Date : Sun Feb 13 2005 09:18 am

David Schwartz wrote:
> "Gianni Mariani" <gi2nospam@mariani.ws> wrote in message 
> news:kNCdnWBwbqDJ7pPfRVn-pA@speakeasy.net...

> 
>     I can't follow Gianni Mariana's points at all. If the COFU has already 
> been initialized, the COFU code reduces to:
> 
> acquire_mutex();
> if(false) initialize_object();
> release_mutex();

I can't see why acquire_mutex()/release_mutex() does anything, why have 
this discussion ?

You can't, in general, call all your local static constructors before 
main() (or before a threads start) is called.

e.g.

void Method( T1 & v1 )
{
	static T2  v2( v1 );
}

If v1 is a paramater that is only known after threads start, how can you 
possibly construct v2 before threads are started ?

In many cases, you don't know where a local static is used.  It could be 
used in libraries that you don't control.  There may also be instances 
of templates you really don't have control over.  I think it's 
impractical to impose the requirement you suggest.

.