Re: [Boost-users] std::vector< boost::shared_ptr<int> >::pop_back()

From: Boris Breidenbach (Boris.Breidenbach_at_[hidden])
Date: 2006-07-10 09:29:50

On Mon, Jul 10, 2006 at 03:58:19PM +1000, bringiton bringiton wrote:
> This question is based on curiosity. How does std::vector::pop_back() call
> the destructor of the item getting removed?
> 
> i understood std::vector to be a contigious array of memory, therefore an
> item's memory does not go out of scope when being popped. ie the item goes
> out of scope when the entire array goes out of scope.

just look at the include files:

bits/stl_vector.h says: 
void
      pop_back()
      {
        --this->_M_impl._M_finish;
        std::_Destroy(this->_M_impl._M_finish);
      }

so the destructor is called in std::_Destroy.  Which can be found in
bits/stl_construct.h:
/**
   * @if maint
   * Destroy the object pointed to by a pointer type.
   * @endif
   */
  template<typename _Tp>
    inline void
    _Destroy(_Tp* __pointer)
    { __pointer->~_Tp(); }

It just calls the destructor.