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## Macro BOOST_TTI_TRAIT_HAS_FUNCTION

BOOST_TTI_TRAIT_HAS_FUNCTION — A macro which expands to a metafunction which tests whether a member function or a static member function with a particular name and signature exists.

## Synopsis

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

    BOOST_TTI_TRAIT_HAS_FUNCTION(trait, name)

## Description

BOOST_TTI_TRAIT_HAS_FUNCTION is a macro which expands to a metafunction. The metafunction tests whether a member function or a static member function with a particular name and signature exists. The macro takes the form of BOOST_TTI_TRAIT_HAS_FUNCTION(trait,name) where

trait = the name of the metafunction
name = the name of the inner member.

BOOST_TTI_TRAIT_HAS_FUNCTION generates a metafunction called "trait" where 'trait' is the macro parameter.

    template<class BOOST_TTI_TP_T,class BOOST_TTI_TP_R,class BOOST_TTI_TP_FS,class BOOST_TTI_TP_TAG>
    struct trait
      {
      static const value = unspecified;
      typedef mpl::bool_<true-or-false> type;
      };

    The metafunction types and return:

      BOOST_TTI_TP_T   = the enclosing type in which to look for our 'name'.
                         The enclosing type can be a class, struct, or union.

      BOOST_TTI_TP_R   = the return type of the function

      BOOST_TTI_TP_FS  = (optional) the parameters of the function as a boost::mpl forward sequence
                if function parameters are not empty.

      BOOST_TTI_TP_TAG = (optional) a boost::function_types tag to apply to the function
                if the need for a tag exists.

      returns = 'value' is true if the 'name' exists,
                with the appropriate static member function type,
                otherwise 'value' is false.