Iterating over thread local storage variables

[sigod via Digitalmars-d-learn]

On Friday, 11 March 2016 at 17:03:38 UTC, Anonymouse wrote:
> On Friday, 11 March 2016 at 15:21:38 UTC, maik klein wrote:
>>     static Singleton!T get()
>>     {
>>         if (!instantiated_)
>>             {
>>             synchronized(Singleton!T.classinfo){
>>                 if (!instance_){
>>                     instance_ = new Singleton!T();
>>                 }
>>                 instantiated_ = true;
>>                 instance_.tls.insertBack(&instance_.value);
>
> As a drive-by comment, mind that there is a race there. 
> _instantiated may have been set after the if statement but 
> before the synchronized block. You have to test it again inside.

That's why inside of `synchronized` block you can see `if 
(!instance_)`.

Watch this for details: 
https://www.youtube.com/watch?v=yMNMV9JlkcQ&t=27m54s