Class optional_base

ext/include/boost/optional/optional.hpp:123–784

template<class T>
class optional_base : public optional_tag
{
  private :

    typedef aligned_storage<T> storage_type ;
    typedef optional_base<T> this_type ;

  protected :

    typedef T value_type ;
    typedef typename boost::remove_const<T>::type unqualified_value_type;

  protected:
    typedef T &       reference_type ;
    typedef T const&  reference_const_type ;
#ifndef  BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
    typedef T &&  rval_reference_type ;
    typedef T &&  reference_type_of_temporary_wrapper ;
#endif
    typedef T *         pointer_type ;
    typedef T const*    pointer_const_type ;
    typedef T const&    argument_type ;

    // Creates an optional<T> uninitialized.
    // No-throw
    optional_base()
      :
      m_initialized(false) {}

    // Creates an optional<T> uninitialized.
    // No-throw
    optional_base ( none_t )
      :
      m_initialized(false) {}

    // Creates an optional<T> initialized with 'val'.
    // Can throw if T::T(T const&) does
    optional_base ( init_value_tag, argument_type val )
      :
      m_initialized(false)
    {
        construct(val);
    }

#ifndef  BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
    // move-construct an optional<T> initialized from an rvalue-ref to 'val'.
    // Can throw if T::T(T&&) does
    optional_base ( init_value_tag, rval_reference_type val )
      :
      m_initialized(false)
    {
      construct( boost::move(val) );
    }
#endif

    // Creates an optional<T> initialized with 'val' IFF cond is true, otherwise creates an uninitialized optional<T>.
    // Can throw if T::T(T const&) does
    optional_base ( bool cond, argument_type val )