llvm/libcxx/test/std/diagnostics/syserr/syserr.hash/error_code.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
//
//===----------------------------------------------------------------------===//

// <system_error>
//
// template <>
// struct hash<error_code>;

#include <system_error>
#include <cassert>
#include <cstddef>
#include <functional>
#include <type_traits>

#include "test_macros.h"

void
test(int i)
{
    typedef std::error_code T;
    typedef std::hash<T> H;
#if TEST_STD_VER <= 14
    static_assert((std::is_same<H::argument_type, T>::value), "" );
    static_assert((std::is_same<H::result_type, std::size_t>::value), "" );
#endif
    ASSERT_NOEXCEPT(H()(T()));
    H h;
    T ec(i, std::system_category());
    const std::size_t result = h(ec);
    LIBCPP_ASSERT(result == static_cast<std::size_t>(i));
    ((void)result); // Prevent unused warning
}

int main(int, char**)
{
    test(0);
    test(2);
    test(10);

  return 0;
}