NAME¶

std::ranges::sized_range,std::ranges::disable_sized_range - std::ranges::sized_range,std::ranges::disable_sized_range

Synopsis¶

Defined in header <ranges>
template< class T >

concept sized_range = ranges::range<T> &&
requires(T& t) { (1) (since C++20)
ranges::size(t);

};
template< class > (2) (since C++20)
inline constexpr bool disable_sized_range = false;

1) The sized_range concept specifies the requirements of a range type that knows its
size in constant time with the size function.
2) disable_sized_range exists to allow use of range types that provide a size
function (either as a member or as a non-member) but do not in fact model
sized_range. Users may specialize disable_sized_range for cv-unqualified
program-defined types. Such specializations shall be usable in constant expressions
and have type const bool.

Notes¶

disable_sized_range cannot be used to opt-out a range whose iterator and sentinel
satisfy sized_sentinel_for; std::disable_sized_sentinel_for must be used instead.

disable_sized_range cannot be specialized for array types or reference types.

Example¶

// Run this code

#include <forward_list>
#include <list>
#include <ranges>

static_assert
(
std::ranges::sized_range<std::list<int>> and
not std::ranges::sized_range<std::forward_list<int>>
);

int main() {}

See also¶

ranges::random_access_range specifies a range whose iterator type satisfies
(C++20) random_access_iterator
(concept)
ranges::contiguous_range specifies a range whose iterator type satisfies
(C++20) contiguous_iterator
(concept)