[cpp-threads] Memory modelcounterproposal:synchronizationoperations

[Alexander Terekhov]

On 5/27/05, Peter Dimov <pdimov at mmltd.net> wrote:
[...]
> Typical DCL:
> 
> X * volatile p = 0;
> mutex mx;
> 
> X * get()
> {
>    if( p == 0 )
>    {
>        mx.lock();
> 
>        if( p == 0 )
>        {
>            p = new X;
>        }
> 
>        mx.unlock();
>    }
> 
>    return p;
> }
> 
> Idiomatic MT C++ replacement:
> 
> X * get()
> {
>    /*protected*/ static X * p = new X;

static(synchronized) X * p = new X;

>    return p;
> }

Plus future_std::once<T> functor for dynamic context. 

regards,
alexander.