[boost] Re: Re: Singleton

From: Pavel Vozenilek (pavel_vozenilek_at_[hidden])
Date: 2005-01-08 18:00:25

"Jason Hise" wrote:

> I have recently converted my code to CRTP form and noticed an inherent 
> problem with creating an allocator template now.  Because the derived 
> class is the final singleton class, and its ctor and dtor are protected, 
> there is no way to give a generic allocator the right to create the 
> object.
Allocator just allocates N bytes, object creates itself via
placement new.

   static T * Create (  )
   {
       void * p = Allocator::allocate(sizeof(T));
       try
       {
           return new (p) T(...);
       }
       catch ( ... )
        {
            Allocator::deallocate(p);
            throw;
        }
    }

Instead of try/catch shared_array should be used to avoid
destroying stack frame when exception throws.

/Pavel