result_of_test.cpp

C++的一个好库。。。现在很流行

// Boost result_of library

//  Copyright Douglas Gregor 2003-2004. Use, modification and
//  distribution is subject to the Boost Software License, Version
//  1.0. (See accompanying file LICENSE_1_0.txt or copy at
//  http://www.boost.org/LICENSE_1_0.txt)

// For more information, see http://www.boost.org/libs/utility
#include <boost/utility/result_of.hpp>
#include <utility>
#include <boost/static_assert.hpp>
#include <boost/type_traits/is_same.hpp>

struct int_result_type { typedef int result_type; };

struct int_result_of
{
  template<typename F> struct result { typedef int type; };
};

struct int_result_type_and_float_result_of
{
  typedef int result_type;
  template<typename F> struct result { typedef float type; };
};

struct X {};

int main()
{
  using namespace boost;

  typedef int (*func_ptr)(float, double);
  typedef int (&func_ref)(float, double);
  typedef int (X::*mem_func_ptr)(float);
  typedef int (X::*mem_func_ptr_c)(float) const;
  typedef int (X::*mem_func_ptr_v)(float) volatile;
  typedef int (X::*mem_func_ptr_cv)(float) const volatile;

  BOOST_STATIC_ASSERT((is_same<result_of<int_result_type(float)>::type, int>::value));
  BOOST_STATIC_ASSERT((is_same<result_of<int_result_of(double)>::type, int>::value));
  BOOST_STATIC_ASSERT((is_same<result_of<int_result_of(void)>::type, void>::value));
  BOOST_STATIC_ASSERT((is_same<result_of<const int_result_of(double)>::type, int>::value));
  BOOST_STATIC_ASSERT((is_same<result_of<volatile int_result_of(void)>::type, void>::value));
  BOOST_STATIC_ASSERT((is_same<result_of<int_result_type_and_float_result_of(char)>::type, int>::value));
  BOOST_STATIC_ASSERT((is_same<result_of<func_ptr(char, float)>::type, int>::value));
  BOOST_STATIC_ASSERT((is_same<result_of<func_ref(char, float)>::type, int>::value));
  BOOST_STATIC_ASSERT((is_same<result_of<mem_func_ptr(X,char)>::type, int>::value));
  BOOST_STATIC_ASSERT((is_same<result_of<mem_func_ptr_c(X,char)>::type, int>::value));
  BOOST_STATIC_ASSERT((is_same<result_of<mem_func_ptr_v(X,char)>::type, int>::value));
  BOOST_STATIC_ASSERT((is_same<result_of<mem_func_ptr_cv(X,char)>::type, int>::value));
  return 0;
}