Boost C++ Libraries

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Struct template valid_member_type

boost::tti::valid_member_type — A metafunction which checks whether the member 'type' returned from invoking the macro metafunction generated by BOOST_TTI_MEMBER_TYPE ( BOOST_TTI_TRAIT_MEMBER_TYPE ) is a valid type.

Synopsis

// In header: <boost/tti/member_type.hpp>

template<typename BOOST_TTI_TP_T, 
         typename BOOST_TTI_TP_MARKER_TYPE = BOOST_TTI_NAMESPACE::detail::notype> 
struct valid_member_type : public boost::mpl::not_< boost::is_same< BOOST_TTI_TP_T, BOOST_TTI_TP_MARKER_TYPE > >
{
};

Description

The metafunction 'valid_member_type', which is in the boost::tti namespace, takes the form of:

template<class BOOST_TTI_TP_T,class BOOST_TTI_TP_MARKER_TYPE = boost::tti::detail::notype>
struct valid_member_type
  {
  static const value = unspecified;
  typedef mpl::bool_<true-or-false> type;
  };

The metafunction types and return:

  BOOST_TTI_TP_T           = returned inner 'type' from invoking the macro metafunction generated by BOOST_TTI_MEMBER_TYPE ( BOOST_TTI_TRAIT_MEMBER_TYPE ).
  
  BOOST_TTI_TP_MARKER_TYPE = (optional) a type to use as the marker type.
                             defaults to the internal boost::tti::detail::notype.

  returns                  = 'value' is true if the type is valid, otherwise 'value' is false.
                             A valid type means that the returned inner 'type' is not the marker type.