Re: Will Modern C++ Design ever get fixed?

Witold Kuzminski<witold.kuzminski@gmail.com> writes:


How can one do something about it _non-portably_?

E.g., if the single-time initialization of `shared_field' (only called
when shared_field == NULL) looks like:

   {
     LockGuard guard (lock);

     if (! shared_field)
       {
         local_variable = make_expensive_data_structure ();
         MEMORY_BARRIER ();
         shared_field = local_variable;
       }
   }

where "MEMORY_BARRIER" is __sync_synchronize or equivalent (both acts
as a compiler memory-barrier and emits an appropriate CPU-specific
memory-barrier instruction or whatever).

Then I guess one could encapsulate that in a class that used the
efficient technique on systems where some MEMORY_BARRIER was available
(90% ?), and an explicit lock or something on anything else.

Thanks,

-miles