std::char_traits<char>::eq/lt, std::char_traits<wchar_t>::eq/lt, std::char_traits<char8_t>::eq/lt, std::char_traits<char16_t>::eq/lt, std::char_traits<char32_t>::eq/lt

static bool eq( char_type a, char_type b );	(1)	(constexpr since C++11) (noexcept since C++11)
static bool lt( char_type a, char_type b );	(2)	(constexpr since C++11) (noexcept since C++11)

Compares two characters.

1) Compares a and b for equality, behaves identically to

static_cast<unsigned char>(a) == static_cast<unsigned char>(b), if char_type is char,
a == b otherwise.

2) Compares a and b in such a way that they are totally ordered, behaves identically to

static_cast<unsigned char>(a) < static_cast<unsigned char>(b), if char_type is char,
a < b otherwise.

See CharTraits for the general requirements on character traits for X::eq and X::lt.

a, b

character values to compare

1) true if a and b are equal, false otherwise.

2) true if a is less than b, false otherwise.

Constant.

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR	Applied to	Behavior as published	Correct behavior
LWG 467	C++98	for std::char_traits<char>, the semantics of `eq()` and `lt()` are the same as the built-in `==` and `<` on char respectively^[1]	changed to built-in `==` and `<` on unsignedchar

Most implementations call std::memcmp() for efficiency, which interprets the data as arrays of unsignedchar. If char is signed on such implementations, std::char_traits<char> fails to satisfy the requirements of CharTraits.

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