libcxx/test/std/strings/basic.string/string.ops/string.accessors/c_str.pass.cpp

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

// <string>

// const charT* c_str() const; // constexpr since C++20

#include <string>
#include <cassert>

#include "test_macros.h"
#include "min_allocator.h"

template <class S>
TEST_CONSTEXPR_CXX20 void test(const S& s) {
  typedef typename S::traits_type T;
  const typename S::value_type* str = s.c_str();
  if (s.size() > 0) {
    assert(T::compare(str, &s[0], s.size()) == 0);
    assert(T::eq(str[s.size()], typename S::value_type()));
  } else
    assert(T::eq(str[0], typename S::value_type()));
}

template <class S>
TEST_CONSTEXPR_CXX20 void test_string() {
  test(S(""));
  test(S("abcde"));
  test(S("abcdefghij"));
  test(S("abcdefghijklmnopqrst"));
}

TEST_CONSTEXPR_CXX20 bool test() {
  test_string<std::string>();
#if TEST_STD_VER >= 11
  test_string<std::basic_string<char, std::char_traits<char>, min_allocator<char> > >();
#endif

  return true;
}

int main(int, char**) {
  test();
#if TEST_STD_VER > 17
  static_assert(test());
#endif

  return 0;
}