1 // Boost result_of library
2
3 // Copyright Douglas Gregor 2003-2004. Use, modification and
4 // distribution is subject to the Boost Software License, Version
5 // 1.0. (See accompanying file LICENSE_1_0.txt or copy at
6 // http://www.boost.org/LICENSE_1_0.txt)
7
8 // Examples:
9 // To run the default test:
10 // $ cd libs/utility/test && bjam
11 // To test decltype on g++ 2.7:
12 // $ cd libs/utility/test && bjam cxxflags="-std=c++11 -D BOOST_RESULT_OF_USE_DECLTYPE"
13
14 #include <boost/config.hpp>
15
16 // For more information, see http://www.boost.org/libs/utility
17 #include <boost/utility/result_of.hpp>
18 #include <utility>
19 #include <boost/static_assert.hpp>
20 #include <boost/type_traits/is_same.hpp>
21
22 struct int_result_type
23 {
24 typedef int result_type;
25 result_type operator()(float);
26 };
27
28 struct int_result_of
29 {
30 template<typename F> struct result { typedef int type; };
31 result<int_result_of(double)>::type operator()(double);
32 result<const int_result_of(double)>::type operator()(double) const;
33 result<int_result_of()>::type operator()();
34 result<volatile int_result_of()>::type operator()() volatile;
35 };
36
37 struct int_result_type_and_float_result_of_and_char_return
38 {
39 typedef int result_type;
40 template<typename F> struct result { typedef float type; };
41 char operator()(char);
42 };
43
44 template<typename T>
45 struct int_result_type_template
46 {
47 typedef int result_type;
48 result_type operator()(float);
49 };
50
51 template<typename T>
52 struct int_result_of_template
53 {
54 template<typename F> struct result;
55 template<typename This, typename That> struct result<This(That)> { typedef int type; };
56 typename result<int_result_of_template<T>(double)>::type operator()(double);
57 typename result<const int_result_of_template<T>(double)>::type operator()(double) const;
58 typename result<int_result_of_template<T>(double)>::type operator()();
59 typename result<volatile int_result_of_template<T>(double)>::type operator()() volatile;
60 };
61
62 template<typename T>
63 struct int_result_type_and_float_result_of_and_char_return_template
64 {
65 typedef int result_type;
66 template<typename F> struct result;
67 template<typename This, typename That> struct result<This(That)> { typedef float type; };
68 char operator()(char);
69 };
70
71 template<typename T>
72 struct cv_overload_check {};
73
74 struct result_of_member_function_template
75 {
76 template<typename F> struct result;
77
78 template<typename This, typename That> struct result<This(That)> { typedef That type; };
79 template<class T> typename result<result_of_member_function_template(T)>::type operator()(T);
80
81 template<typename This, typename That> struct result<const This(That)> { typedef cv_overload_check<const That> type; };
82 template<class T> typename result<const result_of_member_function_template(T)>::type operator()(T) const;
83
84 template<typename This, typename That> struct result<volatile This(That)> { typedef cv_overload_check<volatile That> type; };
85 template<class T> typename result<volatile result_of_member_function_template(T)>::type operator()(T) volatile;
86
87 template<typename This, typename That> struct result<const volatile This(That)> { typedef cv_overload_check<const volatile That> type; };
88 template<class T> typename result<const volatile result_of_member_function_template(T)>::type operator()(T) const volatile;
89
90 template<typename This, typename That> struct result<This(That &, That)> { typedef That & type; };
91 template<class T> typename result<result_of_member_function_template(T &, T)>::type operator()(T &, T);
92
93 template<typename This, typename That> struct result<This(That const &, That)> { typedef That const & type; };
94 template<class T> typename result<result_of_member_function_template(T const &, T)>::type operator()(T const &, T);
95
96 template<typename This, typename That> struct result<This(That volatile &, That)> { typedef That volatile & type; };
97 template<class T> typename result<result_of_member_function_template(T volatile &, T)>::type operator()(T volatile &, T);
98
99 template<typename This, typename That> struct result<This(That const volatile &, That)> { typedef That const volatile & type; };
100 template<class T> typename result<result_of_member_function_template(T const volatile &, T)>::type operator()(T const volatile &, T);
101 };
102
103 struct no_result_type_or_result
104 {
105 short operator()(double);
106 cv_overload_check<const short> operator()(double) const;
107 cv_overload_check<volatile short> operator()(double) volatile;
108 cv_overload_check<const volatile short> operator()(double) const volatile;
109 int operator()();
110 cv_overload_check<const int> operator()() const;
111 cv_overload_check<volatile int> operator()() volatile;
112 cv_overload_check<const volatile int> operator()() const volatile;
113 #if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
114 short operator()(int&&);
115 int operator()(int&);
116 long operator()(int const&);
117 #endif
118 };
119
120 template<typename T>
121 struct no_result_type_or_result_template
122 {
123 short operator()(double);
124 cv_overload_check<const short> operator()(double) const;
125 cv_overload_check<volatile short> operator()(double) volatile;
126 cv_overload_check<const volatile short> operator()(double) const volatile;
127 int operator()();
128 cv_overload_check<const int> operator()() const;
129 cv_overload_check<volatile int> operator()() volatile;
130 cv_overload_check<const volatile int> operator()() const volatile;
131 #if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
132 short operator()(int&&);
133 int operator()(int&);
134 long operator()(int const&);
135 #endif
136 };
137
138 // sfinae_tests are derived from example code from Joel de Guzman,
139 // which demonstrated the interaction between result_of and SFINAE.
140 template <typename F, typename Arg>
141 typename boost::result_of<F(Arg const&)>::type
sfinae_test(F f,Arg const & arg)142 sfinae_test(F f, Arg const& arg)
143 {
144 return f(arg);
145 }
146
147 template <typename F, typename Arg>
148 typename boost::result_of<F(Arg&)>::type
sfinae_test(F f,Arg & arg)149 sfinae_test(F f, Arg& arg)
150 {
151 return f(arg);
152 }
153
sfinae_test_f(int & i)154 int sfinae_test_f(int& i)
155 {
156 return i;
157 }
158
159 struct X {};
160
main()161 int main()
162 {
163 using namespace boost;
164
165 typedef int (*func_ptr)(float, double);
166 typedef int (&func_ref)(float, double);
167 typedef int (*func_ptr_0)();
168 typedef int (&func_ref_0)();
169 typedef void (*func_ptr_void)(float, double);
170 typedef void (&func_ref_void)(float, double);
171 typedef void (*func_ptr_void_0)();
172 typedef void (&func_ref_void_0)();
173 typedef int (X::*mem_func_ptr)(float);
174 typedef int (X::*mem_func_ptr_c)(float) const;
175 typedef int (X::*mem_func_ptr_v)(float) volatile;
176 typedef int (X::*mem_func_ptr_cv)(float) const volatile;
177 typedef int (X::*mem_func_ptr_0)();
178
179 BOOST_STATIC_ASSERT((is_same<result_of<int_result_type(float)>::type, int>::value));
180 BOOST_STATIC_ASSERT((is_same<result_of<int_result_of(double)>::type, int>::value));
181 BOOST_STATIC_ASSERT((is_same<result_of<const int_result_of(double)>::type, int>::value));
182 BOOST_STATIC_ASSERT((is_same<result_of<int_result_type_template<void>(float)>::type, int>::value));
183 BOOST_STATIC_ASSERT((is_same<result_of<int_result_of_template<void>(double)>::type, int>::value));
184 BOOST_STATIC_ASSERT((is_same<result_of<const int_result_of_template<void>(double)>::type, int>::value));
185
186 BOOST_STATIC_ASSERT((is_same<tr1_result_of<int_result_type(float)>::type, int>::value));
187 BOOST_STATIC_ASSERT((is_same<tr1_result_of<int_result_of(double)>::type, int>::value));
188 BOOST_STATIC_ASSERT((is_same<tr1_result_of<const int_result_of(double)>::type, int>::value));
189 BOOST_STATIC_ASSERT((is_same<tr1_result_of<int_result_type_template<void>(float)>::type, int>::value));
190 BOOST_STATIC_ASSERT((is_same<tr1_result_of<int_result_of_template<void>(double)>::type, int>::value));
191 BOOST_STATIC_ASSERT((is_same<tr1_result_of<const int_result_of_template<void>(double)>::type, int>::value));
192
193 BOOST_STATIC_ASSERT((is_same<tr1_result_of<int_result_of(void)>::type, void>::value));
194 BOOST_STATIC_ASSERT((is_same<tr1_result_of<volatile int_result_of(void)>::type, void>::value));
195 BOOST_STATIC_ASSERT((is_same<tr1_result_of<int_result_of_template<void>(void)>::type, void>::value));
196 BOOST_STATIC_ASSERT((is_same<tr1_result_of<volatile int_result_of_template<void>(void)>::type, void>::value));
197
198 // Prior to decltype, result_of could not deduce the return type
199 // of nullary function objects unless they exposed a result_type.
200 #if defined(BOOST_RESULT_OF_USE_DECLTYPE)
201 BOOST_STATIC_ASSERT((is_same<result_of<int_result_of(void)>::type, int>::value));
202 BOOST_STATIC_ASSERT((is_same<result_of<volatile int_result_of(void)>::type, int>::value));
203 BOOST_STATIC_ASSERT((is_same<result_of<int_result_of_template<void>(void)>::type, int>::value));
204 BOOST_STATIC_ASSERT((is_same<result_of<volatile int_result_of_template<void>(void)>::type, int>::value));
205 #else
206 BOOST_STATIC_ASSERT((is_same<result_of<int_result_of(void)>::type, void>::value));
207 BOOST_STATIC_ASSERT((is_same<result_of<volatile int_result_of(void)>::type, void>::value));
208 BOOST_STATIC_ASSERT((is_same<result_of<int_result_of_template<void>(void)>::type, void>::value));
209 BOOST_STATIC_ASSERT((is_same<result_of<volatile int_result_of_template<void>(void)>::type, void>::value));
210 #endif
211
212 // Prior to decltype, result_of ignored a nested result<> if
213 // result_type was defined. After decltype, result_of deduces the
214 // actual return type of the function object, ignoring both
215 // result<> and result_type.
216 #if defined(BOOST_RESULT_OF_USE_DECLTYPE)
217 BOOST_STATIC_ASSERT((is_same<result_of<int_result_type_and_float_result_of_and_char_return(char)>::type, char>::value));
218 BOOST_STATIC_ASSERT((is_same<result_of<int_result_type_and_float_result_of_and_char_return_template<void>(char)>::type, char>::value));
219 #else
220 BOOST_STATIC_ASSERT((is_same<result_of<int_result_type_and_float_result_of_and_char_return(char)>::type, int>::value));
221 BOOST_STATIC_ASSERT((is_same<result_of<int_result_type_and_float_result_of_and_char_return_template<void>(char)>::type, int>::value));
222 #endif
223
224 BOOST_STATIC_ASSERT((is_same<tr1_result_of<int_result_type_and_float_result_of_and_char_return(char)>::type, int>::value));
225 BOOST_STATIC_ASSERT((is_same<tr1_result_of<int_result_type_and_float_result_of_and_char_return_template<void>(char)>::type, int>::value));
226
227 BOOST_STATIC_ASSERT((is_same<result_of<func_ptr(char, float)>::type, int>::value));
228 BOOST_STATIC_ASSERT((is_same<result_of<func_ref(char, float)>::type, int>::value));
229 BOOST_STATIC_ASSERT((is_same<result_of<func_ptr_0()>::type, int>::value));
230 BOOST_STATIC_ASSERT((is_same<result_of<func_ref_0()>::type, int>::value));
231 BOOST_STATIC_ASSERT((is_same<result_of<func_ptr_void(char, float)>::type, void>::value));
232 BOOST_STATIC_ASSERT((is_same<result_of<func_ref_void(char, float)>::type, void>::value));
233 BOOST_STATIC_ASSERT((is_same<result_of<func_ptr_void_0()>::type, void>::value));
234 BOOST_STATIC_ASSERT((is_same<result_of<func_ref_void_0()>::type, void>::value));
235 BOOST_STATIC_ASSERT((is_same<result_of<mem_func_ptr(X,char)>::type, int>::value));
236 BOOST_STATIC_ASSERT((is_same<result_of<mem_func_ptr_c(X,char)>::type, int>::value));
237 BOOST_STATIC_ASSERT((is_same<result_of<mem_func_ptr_v(X,char)>::type, int>::value));
238 BOOST_STATIC_ASSERT((is_same<result_of<mem_func_ptr_cv(X,char)>::type, int>::value));
239 BOOST_STATIC_ASSERT((is_same<result_of<mem_func_ptr_0(X)>::type, int>::value));
240
241 BOOST_STATIC_ASSERT((is_same<tr1_result_of<func_ptr(char, float)>::type, int>::value));
242 BOOST_STATIC_ASSERT((is_same<tr1_result_of<func_ref(char, float)>::type, int>::value));
243 BOOST_STATIC_ASSERT((is_same<tr1_result_of<func_ptr_0()>::type, int>::value));
244 BOOST_STATIC_ASSERT((is_same<tr1_result_of<func_ref_0()>::type, int>::value));
245 BOOST_STATIC_ASSERT((is_same<tr1_result_of<func_ptr_void(char, float)>::type, void>::value));
246 BOOST_STATIC_ASSERT((is_same<tr1_result_of<func_ref_void(char, float)>::type, void>::value));
247 BOOST_STATIC_ASSERT((is_same<tr1_result_of<func_ptr_void_0()>::type, void>::value));
248 BOOST_STATIC_ASSERT((is_same<tr1_result_of<func_ref_void_0()>::type, void>::value));
249 BOOST_STATIC_ASSERT((is_same<tr1_result_of<mem_func_ptr(X,char)>::type, int>::value));
250 BOOST_STATIC_ASSERT((is_same<tr1_result_of<mem_func_ptr_c(X,char)>::type, int>::value));
251 BOOST_STATIC_ASSERT((is_same<tr1_result_of<mem_func_ptr_v(X,char)>::type, int>::value));
252 BOOST_STATIC_ASSERT((is_same<tr1_result_of<mem_func_ptr_cv(X,char)>::type, int>::value));
253 BOOST_STATIC_ASSERT((is_same<tr1_result_of<mem_func_ptr_0(X)>::type, int>::value));
254 BOOST_STATIC_ASSERT((is_same<tr1_result_of<func_ptr(void)>::type, int>::value));
255 BOOST_STATIC_ASSERT((is_same<tr1_result_of<func_ref(void)>::type, int>::value));
256
257 BOOST_STATIC_ASSERT((is_same<result_of<result_of_member_function_template(double)>::type, double>::value));
258 BOOST_STATIC_ASSERT((is_same<result_of<const result_of_member_function_template(double)>::type, cv_overload_check<const double> >::value));
259 BOOST_STATIC_ASSERT((is_same<result_of<volatile result_of_member_function_template(double)>::type, cv_overload_check<volatile double> >::value));
260 BOOST_STATIC_ASSERT((is_same<result_of<const volatile result_of_member_function_template(double)>::type, cv_overload_check<const volatile double> >::value));
261 BOOST_STATIC_ASSERT((is_same<result_of<result_of_member_function_template(int &, int)>::type, int &>::value));
262 BOOST_STATIC_ASSERT((is_same<result_of<result_of_member_function_template(int const &, int)>::type, int const &>::value));
263 BOOST_STATIC_ASSERT((is_same<result_of<result_of_member_function_template(int volatile &, int)>::type, int volatile &>::value));
264 BOOST_STATIC_ASSERT((is_same<result_of<result_of_member_function_template(int const volatile &, int)>::type, int const volatile &>::value));
265
266 BOOST_STATIC_ASSERT((is_same<tr1_result_of<result_of_member_function_template(double)>::type, double>::value));
267 BOOST_STATIC_ASSERT((is_same<tr1_result_of<const result_of_member_function_template(double)>::type, cv_overload_check<const double> >::value));
268 BOOST_STATIC_ASSERT((is_same<tr1_result_of<volatile result_of_member_function_template(double)>::type, cv_overload_check<volatile double> >::value));
269 BOOST_STATIC_ASSERT((is_same<tr1_result_of<const volatile result_of_member_function_template(double)>::type, cv_overload_check<const volatile double> >::value));
270 BOOST_STATIC_ASSERT((is_same<tr1_result_of<result_of_member_function_template(int &, int)>::type, int &>::value));
271 BOOST_STATIC_ASSERT((is_same<tr1_result_of<result_of_member_function_template(int const &, int)>::type, int const &>::value));
272 BOOST_STATIC_ASSERT((is_same<tr1_result_of<result_of_member_function_template(int volatile &, int)>::type, int volatile &>::value));
273 BOOST_STATIC_ASSERT((is_same<tr1_result_of<result_of_member_function_template(int const volatile &, int)>::type, int const volatile &>::value));
274
275 typedef int (*pf_t)(int);
276 BOOST_STATIC_ASSERT((is_same<result_of<pf_t(int)>::type, int>::value));
277 BOOST_STATIC_ASSERT((is_same<result_of<pf_t const(int)>::type,int>::value));
278
279 BOOST_STATIC_ASSERT((is_same<tr1_result_of<pf_t(int)>::type, int>::value));
280 BOOST_STATIC_ASSERT((is_same<tr1_result_of<pf_t const(int)>::type,int>::value));
281
282 #if defined(BOOST_RESULT_OF_USE_DECLTYPE) || defined(BOOST_RESULT_OF_USE_TR1_WITH_DECLTYPE_FALLBACK)
283 BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result(double)>::type, short>::value));
284 BOOST_STATIC_ASSERT((is_same<result_of<const no_result_type_or_result(double)>::type, cv_overload_check<const short> >::value));
285 BOOST_STATIC_ASSERT((is_same<result_of<volatile no_result_type_or_result(double)>::type, cv_overload_check<volatile short> >::value));
286 BOOST_STATIC_ASSERT((is_same<result_of<const volatile no_result_type_or_result(double)>::type, cv_overload_check<const volatile short> >::value));
287 BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result(void)>::type, int>::value));
288 BOOST_STATIC_ASSERT((is_same<result_of<const no_result_type_or_result(void)>::type, cv_overload_check<const int> >::value));
289 BOOST_STATIC_ASSERT((is_same<result_of<volatile no_result_type_or_result(void)>::type, cv_overload_check<volatile int> >::value));
290 BOOST_STATIC_ASSERT((is_same<result_of<const volatile no_result_type_or_result(void)>::type, cv_overload_check<const volatile int> >::value));
291
292 BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_template<void>(double)>::type, short>::value));
293 BOOST_STATIC_ASSERT((is_same<result_of<const no_result_type_or_result_template<void>(double)>::type, cv_overload_check<const short> >::value));
294 BOOST_STATIC_ASSERT((is_same<result_of<volatile no_result_type_or_result_template<void>(double)>::type, cv_overload_check<volatile short> >::value));
295 BOOST_STATIC_ASSERT((is_same<result_of<const volatile no_result_type_or_result_template<void>(double)>::type, cv_overload_check<const volatile short> >::value));
296 BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_template<void>(void)>::type, int>::value));
297 BOOST_STATIC_ASSERT((is_same<result_of<const no_result_type_or_result_template<void>(void)>::type, cv_overload_check<const int> >::value));
298 BOOST_STATIC_ASSERT((is_same<result_of<volatile no_result_type_or_result_template<void>(void)>::type, cv_overload_check<volatile int> >::value));
299 BOOST_STATIC_ASSERT((is_same<result_of<const volatile no_result_type_or_result_template<void>(void)>::type, cv_overload_check<const volatile int> >::value));
300
301 BOOST_STATIC_ASSERT((is_same<result_of<func_ptr&(char, float)>::type, int>::value));
302 BOOST_STATIC_ASSERT((is_same<result_of<func_ptr const&(char, float)>::type, int>::value));
303 BOOST_STATIC_ASSERT((is_same<result_of<int_result_of&(double)>::type, int>::value));
304 BOOST_STATIC_ASSERT((is_same<result_of<int_result_of const&(double)>::type, int>::value));
305
306 #if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
307 BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result(int&&)>::type, short>::value));
308 BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result(int&)>::type, int>::value));
309 BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result(int const&)>::type, long>::value));
310 BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_template<void>(int&&)>::type, short>::value));
311 BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_template<void>(int&)>::type, int>::value));
312 BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_template<void>(int const&)>::type, long>::value));
313 #endif
314 #endif
315
316 #if defined(BOOST_RESULT_OF_USE_DECLTYPE) || defined(BOOST_RESULT_OF_USE_TR1_WITH_DECLTYPE_FALLBACK)
317 int i = 123;
318 sfinae_test(sfinae_test_f, i);
319 #endif // defined(BOOST_RESULT_OF_USE_DECLTYPE) || defined(BOOST_RESULT_OF_USE_TR1_WITH_DECLTYPE_FALLBACK)
320
321 return 0;
322 }
323