std::predicate

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Concepts library

Core language concepts
same_as (C++20)
derived_from (C++20)
convertible_to (C++20)
common_reference_with (C++20)
common_with (C++20)
integral (C++20)
signed_integral (C++20)
unsigned_integral (C++20)
floating_point (C++20)
swappableswappable_with (C++20)(C++20)
destructible (C++20)
constructible_from (C++20)
default_initializable (C++20)
move_constructible (C++20)
copy_constructible (C++20)
assignable_from (C++20)

Comparison concepts
equality_comparableequality_comparable_with (C++20)(C++20)
totally_orderedtotally_ordered_with (C++20)(C++20)
Object concepts
movable (C++20)
copyable (C++20)
semiregular (C++20)
regular (C++20)
Callable concepts
invocableregular_invocable (C++20)(C++20)
predicate (C++20)
relation (C++20)
equivalence_relation (C++20)
strict_weak_order (C++20)

Exposition-only concepts
boolean-testable (C++20)

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Defined in header`<concepts>`
template<class F,class...Args> concept predicate= std::regular_invocable<F, Args...>&& boolean-testable<std::invoke_result_t<F, Args...>>;		(since C++20)

The conceptstd::predicate<F, Args...> specifies thatF is a predicate that accepts arguments whose types and value categories are encoded byArgs..., i.e., it can be invoked with these arguments to produce aboolean-testable result.

Note thatregular_invocable requires the invocation to not modify either the callable object or the arguments and beequality-preserving.