libcxx/test/std/utilities/function.objects/func.memfn/member_function.pass.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 // <functional>
  10
  11 // template<Returnable R, class T, CopyConstructible... Args>
  12 //   unspecified mem_fn(R (T::* pm)(Args...));
  13
  14 #include <functional>
  15 #include <cassert>
  16
  17 #include "test_macros.h"
  18
  19 struct A
  20 {
  21     TEST_CONSTEXPR_CXX14 char test0() {return 'a';}
  22     TEST_CONSTEXPR_CXX14 char test1(int) {return 'b';}
  23     TEST_CONSTEXPR_CXX14 char test2(int, double) {return 'c';}
  24 };
  25
  26 template <class F>
  27 TEST_CONSTEXPR_CXX20 bool
  28 test0(F f)
  29 {
  30     {
  31     A a;
  32     assert(f(a) == 'a');
  33     A* ap = &a;
  34     assert(f(ap) == 'a');
  35     const F& cf = f;
  36     assert(cf(ap) == 'a');
  37     }
  38     return true;
  39 }
  40
  41 template <class F>
  42 TEST_CONSTEXPR_CXX20 bool
  43 test1(F f)
  44 {
  45     {
  46     A a;
  47     assert(f(a, 1) == 'b');
  48     A* ap = &a;
  49     assert(f(ap, 2) == 'b');
  50     const F& cf = f;
  51     assert(cf(ap, 2) == 'b');
  52     }
  53     return true;
  54 }
  55
  56 template <class F>
  57 TEST_CONSTEXPR_CXX20 bool
  58 test2(F f)
  59 {
  60     {
  61     A a;
  62     assert(f(a, 1, 2) == 'c');
  63     A* ap = &a;
  64     assert(f(ap, 2, 3.5) == 'c');
  65     const F& cf = f;
  66     assert(cf(ap, 2, 3.5) == 'c');
  67     }
  68     return true;
  69 }
  70
  71 int main(int, char**)
  72 {
  73     test0(std::mem_fn(&A::test0));
  74     test1(std::mem_fn(&A::test1));
  75     test2(std::mem_fn(&A::test2));
  76 #if TEST_STD_VER >= 11
  77     static_assert((noexcept(std::mem_fn(&A::test0))), ""); // LWG#2489
  78 #endif
  79
  80 #if TEST_STD_VER >= 20
  81     static_assert(test0(std::mem_fn(&A::test0)));
  82     static_assert(test1(std::mem_fn(&A::test1)));
  83     static_assert(test2(std::mem_fn(&A::test2)));
  84 #endif
  85
  86     return 0;
  87 }