std::cmp_equal, cmp_not_equal, cmp_less, cmp_greater, cmp_less_equal, cmp_greater_equal

 

C++

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Standard Library Headers

Freestanding and hosted implementations

Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

Utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Localizations library

Input/output library

Filesystem library (C++17)

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Technical Specifications

 

Utilities library

Language support Type support (basic types, RTTI, type traits) Library feature-test macros (C++20) Dynamic memory management Program utilities Error handling Coroutine support (C++20) Variadic functions launder (C++17) initializer_list (C++11) source_location (C++20) Three-way comparison (C++20) three_way_comparablethree_way_comparable_with (C++20)(C++20) strong_ordering (C++20) weak_ordering (C++20) partial_ordering (C++20) common_comparison_category (C++20) compare_three_way_result (C++20) compare_three_way (C++20) strong_order (C++20) weak_order (C++20) partial_order (C++20) compare_strong_order_fallback (C++20) compare_weak_order_fallback (C++20) compare_partial_order_fallback (C++20) is_eqis_neqis_ltis_lteqis_gtis_gteq (C++20)(C++20)(C++20)(C++20)(C++20)(C++20)

General utilities Date and time Function objects Formatting library (C++20) bitset hash (C++11) integer_sequence (C++14) Relational operators (deprecated in C++20) rel_ops::operator!=rel_ops::operator>rel_ops::operator<=rel_ops::operator>= Integer comparison functions cmp_equalcmp_not_equalcmp_lesscmp_greatercmp_less_thancmp_greater_than (C++20)(C++20)(C++20)(C++20)(C++20)(C++20) in_range (C++20) Swap and type operations swap ranges::swap (C++20) exchange (C++14) declval (C++11) forward (C++11) move (C++11) move_if_noexcept (C++11) as_const (C++17) Common vocabulary types pair tuple (C++11) apply (C++17) make_from_tuple (C++17) optional (C++17) any (C++17) variant (C++17) Elementary string conversions to_chars (C++17) from_chars (C++17) chars_format (C++17)

 

Defined in header <utility>
template< class T, class U > constexpr bool cmp_equal( T t, U u ) noexcept;	(1)	(since C++20)
template< class T, class U > constexpr bool cmp_not_equal( T t, U u ) noexcept;	(2)	(since C++20)
template< class T, class U > constexpr bool cmp_less( T t, U u ) noexcept;	(3)	(since C++20)
template< class T, class U > constexpr bool cmp_greater( T t, U u ) noexcept;	(4)	(since C++20)
template< class T, class U > constexpr bool cmp_less_equal( T t, U u ) noexcept;	(5)	(since C++20)
template< class T, class U > constexpr bool cmp_greater_equal( T t, U u ) noexcept;	(6)	(since C++20)

Compare the values of two integers t and u. Unlike builtin comparison operators, negative signed integers always compare less than (and not equal to) unsigned integers: the comparison is safe against lossy integer conversion.

-1 > 0u; // true
std::cmp_greater(-1, 0u); // false

It is a compile-time error if either T or U is not a signed or unsigned integer type (including standard integer type and extended integer type).

Parameters

t	-	left-hand argument
u	-	right-hand argument

Return value

1) true if t is equal to u.

2) true if t is not equal to u.

3) true if t is less than u.

4) true if t is greater than u.

5) true if t is less or equal to u.

6) true if t is greater or equal to u.

Possible implementation

template< class T, class U > constexpr bool cmp_equal( T t, U u ) noexcept { using UT = std::make_unsigned_t<T>; using UU = std::make_unsigned_t<U>; if constexpr (std::is_signed_v<T> == std::is_signed_v<U>) return t == u; else if constexpr (std::is_signed_v<T>) return t < 0 ? false : UT(t) == u; else return u < 0 ? false : t == UU(u); }   template< class T, class U > constexpr bool cmp_not_equal( T t, U u ) noexcept { return !cmp_equal(t, u); }   template< class T, class U > constexpr bool cmp_less( T t, U u ) noexcept { using UT = std::make_unsigned_t<T>; using UU = std::make_unsigned_t<U>; if constexpr (std::is_signed_v<T> == std::is_signed_v<U>) return t < u; else if constexpr (std::is_signed_v<T>) return t < 0 ? true : UT(t) < u; else return u < 0 ? false : t < UU(u); }   template< class T, class U > constexpr bool cmp_greater( T t, U u ) noexcept { return cmp_less(u, t); }   template< class T, class U > constexpr bool cmp_less_equal( T t, U u ) noexcept { return !cmp_greater(t, u); }   template< class T, class U > constexpr bool cmp_greater_equal( T t, U u ) noexcept { return !cmp_less(t, u); }

Notes

These functions cannot be used to compare std::byte, char, char8_t, char16_t, char32_t, wchar_t and bool.