table of contents
std::experimental::ranges::identity(3) | C++ Standard Libary | std::experimental::ranges::identity(3) |
NAME¶
std::experimental::ranges::identity - std::experimental::ranges::identity
Synopsis¶
Defined in header <experimental/ranges/functional>
struct identity; (ranges TS)
ranges::identity is a function object type whose operator() returns its
argument
unchanged. It is used as the default projection for all Ranges TS
algorithms.
Member types¶
Member type Definition
is_transparent /* unspecified */
Member functions¶
operator() returns the argument unchanged
(public member function)
std::experimental::ranges::identity::operator()
template< class T>
constexpr T&& operator()( T&& t ) const noexcept;
Returns std::forward<T>(t).
Parameters¶
t - argument to return
Return value¶
std::forward<T>(t).
Notes¶
The member type is_transparent indicates to the caller that this
function object is
a transparent function object: it accepts arguments of arbitrary types and
uses
perfect forwarding, which avoids unnecessary copying and conversion when the
function object is used in heterogeneous context, or with rvalue arguments.
In
particular, template functions such as std::set::find and
std::set::lower_bound make
use of this member type on their Compare types.
Example¶
This section is incomplete
Reason: no example
2022.07.31 | http://cppreference.com |