Subj : Re: Can C++ local static objects be made thread safe?
To   : comp.programming.threads
From : Gianni Mariani
Date : Thu Feb 03 2005 06:58 am

David Schwartz wrote:
> "Gianni Mariani" <gi2nospam@mariani.ws> wrote in message 
> news:haGdnR1nYeaWBJzfRVn-tg@speakeasy.net...
> 
> 
>>Simply because the C++ standard is quite specific in that static function 
>>local variables (non POD) must be initialized exactly once on the *first 
>>time* that control passes through the variable.  All we're doing here is 
>>enforcing this requirement.
> 
> 
>     No! The C++ standard says nothing about threads. The C++ standard does 
> not provide *any* guarantees in the context of threads.'

Exactly.  Hence, any platform that supports threads must do so in a way 
that it maintains the requirements of the C++ standard, otherwise it is 
BROKEN.

  A threading standard
> must specifically restate any C++ standard guarantees that it provides in 
> the context of threads. If we're talking POSIX, POSIX specifically requires 
> accesses to shared data (which the static object is) to be protected by 
> mutexes.

Only if the shared data is modified.

.