1 //===----------------------------------------------------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 // <system_error>
11 
12 // class error_category
13 
14 // constexpr error_category() noexcept;
15 
16 #include <system_error>
17 #include <type_traits>
18 #include <string>
19 #include <cassert>
20 
21 #if _LIBCPP_STD_VER > 11
22 
23 class test1
24     : public std::error_category
25 {
26 public:
27     constexpr test1() = default;  // won't compile if error_category() is not constexpr
name() const28     virtual const char* name() const noexcept {return nullptr;}
message(int ev) const29     virtual std::string message(int ev) const {return std::string();}
30 };
31 
32 #endif  // _LIBCPP_STD_VER > 11
33 
main()34 int main()
35 {
36 #if _LIBCPP_STD_VER > 11
37     static_assert(std::is_nothrow_default_constructible<test1>::value,
38                                  "error_category() must exist and be noexcept");
39 #endif  // _LIBCPP_STD_VER > 11
40 }
41