23 Strings library [strings]

23.2 Character traits [char.traits]

23.2.4 char_­traits specializations [char.traits.specializations]

23.2.4.6 struct char_­traits<wchar_­t> [char.traits.specializations.wchar.t]

namespace std { template<> struct char_traits<wchar_t> { using char_type = wchar_t; using int_type = wint_t; using off_type = streamoff; using pos_type = wstreampos; using state_type = mbstate_t; using comparison_category = strong_ordering; static constexpr void assign(char_type& c1, const char_type& c2) noexcept; static constexpr bool eq(char_type c1, char_type c2) noexcept; static constexpr bool lt(char_type c1, char_type c2) noexcept; static constexpr int compare(const char_type* s1, const char_type* s2, size_t n); static constexpr size_t length(const char_type* s); static constexpr const char_type* find(const char_type* s, size_t n, const char_type& a); static constexpr char_type* move(char_type* s1, const char_type* s2, size_t n); static constexpr char_type* copy(char_type* s1, const char_type* s2, size_t n); static constexpr char_type* assign(char_type* s, size_t n, char_type a); static constexpr int_type not_eof(int_type c) noexcept; static constexpr char_type to_char_type(int_type c) noexcept; static constexpr int_type to_int_type(char_type c) noexcept; static constexpr bool eq_int_type(int_type c1, int_type c2) noexcept; static constexpr int_type eof() noexcept; }; }
The two-argument members assign, eq, and lt are defined identically to the built-in operators =, ==, and <, respectively.
The member eof() returns WEOF.