libcxx/test/std/utilities/function.objects/func.memfn/member_data.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> unspecified mem_fn(R T::* pm);
  12
  13 #include <functional>
  14 #include <cassert>
  15
  16 #include "test_macros.h"
  17
  18 struct A
  19 {
  20     double data_;
  21 };
  22
  23 template <class F>
  24 TEST_CONSTEXPR_CXX20 bool
  25 test(F f)
  26 {
  27     {
  28     A a = {0.0};
  29     f(a) = 5;
  30     assert(a.data_ == 5);
  31     A* ap = &a;
  32     f(ap) = 6;
  33     assert(a.data_ == 6);
  34     const A* cap = ap;
  35     assert(f(cap) == f(ap));
  36     const F& cf = f;
  37     assert(cf(ap) == f(ap));
  38     }
  39     return true;
  40 }
  41
  42 int main(int, char**)
  43 {
  44     test(std::mem_fn(&A::data_));
  45
  46 #if TEST_STD_VER >= 20
  47     static_assert(test(std::mem_fn(&A::data_)));
  48 #endif
  49
  50     return 0;
  51 }