# define NOTHROW
#endif
+#if __cplusplus >= 202002L
+# define CONSTEXPR constexpr
+#else
+# define CONSTEXPR
+#endif
+
namespace std {
// lib.char.traits, character traits:
template<class charT>
_GLIBCXX_END_NAMESPACE_CXX11
template<class charT, class traits, class Allocator>
+ CONSTEXPR
basic_string<charT,traits,Allocator>
operator+(const basic_string<charT,traits,Allocator>& lhs,
const basic_string<charT,traits,Allocator>& rhs);
template<class charT, class traits, class Allocator>
+ CONSTEXPR
basic_string<charT,traits,Allocator>
operator+(const charT* lhs,
const basic_string<charT,traits,Allocator>& rhs);
template<class charT, class traits, class Allocator>
+ CONSTEXPR
basic_string<charT,traits,Allocator>
operator+(charT lhs, const basic_string<charT,traits,Allocator>& rhs);
template<class charT, class traits, class Allocator>
+ CONSTEXPR
basic_string<charT,traits,Allocator>
operator+(const basic_string<charT,traits,Allocator>& lhs,
const charT* rhs);
template<class charT, class traits, class Allocator>
+ CONSTEXPR
basic_string<charT,traits,Allocator>
operator+(const basic_string<charT,traits,Allocator>& lhs, charT rhs);
template<class charT, class traits, class Allocator>
+ CONSTEXPR
bool operator==(const basic_string<charT,traits,Allocator>& lhs,
const basic_string<charT,traits,Allocator>& rhs) NOTHROW;
template<class charT, class traits, class Allocator>
- bool operator==(const charT* lhs,
- const basic_string<charT,traits,Allocator>& rhs);
- template<class charT, class traits, class Allocator>
+ CONSTEXPR
bool operator==(const basic_string<charT,traits,Allocator>& lhs,
const charT* rhs);
+
+#if __cpp_lib_three_way_comparison
+ template<class charT, class traits, class Allocator>
+ constexpr
+ bool operator<=>(const basic_string<charT,traits,Allocator>& lhs,
+ const basic_string<charT,traits,Allocator>& rhs) NOTHROW;
+ template<class charT, class traits, class Allocator>
+ constexpr
+ bool operator<=>(const basic_string<charT,traits,Allocator>& lhs,
+ const charT* rhs);
+#else
+ template<class charT, class traits, class Allocator>
+ CONSTEXPR
+ bool operator==(const charT* lhs,
+ const basic_string<charT,traits,Allocator>& rhs);
template<class charT, class traits, class Allocator>
bool operator!=(const basic_string<charT,traits,Allocator>& lhs,
const basic_string<charT,traits,Allocator>& rhs) NOTHROW;
template<class charT, class traits, class Allocator>
bool operator>=(const charT* lhs,
const basic_string<charT,traits,Allocator>& rhs);
+#endif
// lib.string.special:
template<class charT, class traits, class Allocator>
+ CONSTEXPR
void swap(basic_string<charT,traits,Allocator>& lhs,
basic_string<charT,traits,Allocator>& rhs)
#if __cplusplus >= 201103L