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BOOST_TTI_TRAIT_HAS_MEMBER_DATA — Expands to a metafunction which tests whether a member data with a particular name and type exists.


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



trait = the name of the metafunction.

name = the name of the inner member to introspect.

generates a metafunction called "trait" where 'trait' is the macro parameter. template<class BOOST_TTI_TP_ET,class BOOST_TTI_TP_TYPE> struct trait { static const value = unspecified; typedef mpl::bool_<true-or-false> type; }; The metafunction types and return: BOOST_TTI_TP_ET = the enclosing type in which to look for our 'name' OR The type of the member data in the form of a pointer to member data. BOOST_TTI_TP_TYPE = (optional) The type of the member data if the first parameter is the enclosing type. returns = 'value' is true if the 'name' exists, with the correct data type, otherwise 'value' is false.