1[/ 2 Copyright 2014 Peter Dimov 3 4 Distributed under the Boost Software License, Version 1.0. 5 6 See accompanying file LICENSE_1_0.txt 7 or copy at http://boost.org/LICENSE_1_0.txt 8] 9 10[section:is_same is_same] 11 12[simplesect Authors] 13 14* Peter Dimov 15 16[endsimplesect] 17 18[section Header <boost/core/is_same.hpp>] 19 20The header `<boost/core/is_same.hpp>` defines the class template 21`boost::core::is_same<T1,T2>`. It defines a nested integral constant 22`value` which is `true` when `T1` and `T2` are the same type, and 23`false` when they are not. 24 25In tandem with `BOOST_TEST_TRAIT_TRUE` and `BOOST_TEST_TRAIT_FALSE`, 26`is_same` is useful for writing tests for traits classes that have 27to define specific nested types. 28 29[section Synopsis] 30 31`` 32namespace boost 33{ 34 35namespace core 36{ 37 template<class T1, class T2> struct is_same; 38} 39 40} 41`` 42 43[endsect] 44 45[section Example] 46 47`` 48#include <boost/core/lightweight_test_trait.hpp> 49#include <boost/core/is_same.hpp> 50 51template<class T> struct X 52{ 53 typedef T& type; 54}; 55 56using boost::core::is_same; 57 58int main() 59{ 60 BOOST_TEST_TRAIT_TRUE(( is_same<X<int>::type, int&> )); 61 return boost::report_errors(); 62} 63`` 64 65[endsect] 66 67[endsect] 68 69[endsect] 70