Re: [Boost-users] type_with_alignment

14 Jun 2006


      Howard Hinnant  writes:
...
There are applications such as boost::function where aligned storage  
for an unknown type is useful.  In boost::function's case, aligned  
storage could be used to implement the "short string optimization".
And so it is, AFAIK.
...
The general pattern is:
class Container
{
private:
     const unsigned buf_size = ...;
     aligned_storage::type buffer;
public:
     template <class T>
        Container(const T& t) {/* might stick t into buffer instead  
of on heap, based on sizeof(T) */}
};
On Jun 14, 2006, at 6:55 AM, David Abrahams wrote:
...
I think what the OP is looking for is called boost::shared_ptr ;-)
shared_ptr can't compete with this application performance-wise.
Well, it depends how expensive it is to copy your small object.  If it
turns out that T is a vector, and it fits in your local buffer, when
Container is copied it might be a lot cheaper to use shared_ptr.

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com