Subj : Re: Can C++ local static objects be made thread safe?
To   : comp.programming.threads
From : Gianni Mariani
Date : Wed Feb 02 2005 07:44 pm

Giancarlo Niccolai wrote:
> Gianni Mariani wrote:
....
> But adding a mutex lock/unlock with potential useless context swap at each
> object access (because each object access should enter that call and make
> the comp already_initialized,0 atomic), even if i.e. you just wanted to
> read it, or you had to synchronize it afterwards on YOUR rules, it's more
> than silly: it's mad. Especially if you can do it right without it, and
> believe me, you can.

I'm not sure how the GCC compiler implemented this, but I did show some 
code that requires a mutex check only on the first time throught the 
code, otherwise there is no check at all.  C++ already checks for prior 
construction on every pass through the code, this check can be used to 
also eliminate the need to lock a mutex.  The net effect is virtually 0 
overhead.

.