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std::projected_value_t

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Defined in header <iterator>

template< std::indirectly_readable I,

std::indirectly_regular_unary_invocable <I> Proj >
using projected_value_t =

std::remove_cvref_t <std::invoke_result_t <Proj&, std::iter_value_t <I>&>>;

(since C++26)

The alias template projected_value_t obtains the value type by stripping any reference and its topmost cv-qualifiers of the result type of applying Proj to std::iter_value_t <I>&.

projected_value_t is used to determine the default value type in some algorithms such as ranges::contains .

Contents

[edit] Template parameters

I - an indirectly readable type

Proj - projection applied to an lvalue reference to value type of I

[edit] Notes

Feature-test macro	Value	Std	Feature
`__cpp_lib_algorithm_default_value_type`	`202403L`	(C++26)	default template type for algorithm values using `std::projected_value_t`

[edit] Example

This section is incomplete
Reason: no example

[edit] See also

indirect_result_t

(C++20)

computes the result of invoking a callable object on the result of dereferencing some set of indirectly_readable types
(alias template)[edit]

(C++20)

helper template for specifying the constraints on algorithms that accept projections
(alias template)[edit]

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Todo no example