[boost] Uninitialized storage container to delay construction?

From: Aaron W. LaFramboise (aaronrabiddog51_at_[hidden])
Date: 2007-06-03 11:11:33

Does Boost have some sort of uninitialized storage container? 
Presently, I use this pattern if I want to delay construction of a 
sub-object.

class my_class {
   public:
     my_class() {
       // ...
       subobject = auto_ptr<type>(new type(params));
     }
   private:
     auto_ptr<type> subobject;
};

But I'd like something similar that didn't use the heap, but instead 
allocated the storage for the sub-object within the class object itself. 
  Perhaps it would look like this.

class my_class2 {
   public:
     my_class2() {
       // ...
       subobject.construct(params);
     }
   private:
     uninitialized_container<type> subobject;
};

A TR1 array<T, sizeof(T)> almost works, except for these points:
   (1) It doesn't provide proper alignment guarantees.
   (2) It doesn't call the destructor when it is destroyed.

So, does Boost have any such thing?