Defined in header
template< class T >
concept sized_range = ranges::range<T> &&
inline constexpr bool disable_sized_range = false;
Formally, given an lvalue t of type std::remove_reference_t<T>, T models sized_range only if
- has amortized constant-time complexity,
- does not modify t, and
- is equal to ranges::distance(t), and
- if iterator_t<T> models forward_iterator, ranges::size(t) is well-defined regardless of the evaluation of ranges::begin(t) (in other words, a single-pass sized range may support a call to size only before the first call to begin, but a forward range must support size at all times)
sizefunction (either as a member or as a non-member) that satisfy but do not in fact model sized_range. Users may specialize
disable_sized_rangefor cv-unqualified program-defined types. Such specializations shall be usable in constant expressions and have type
disable_sized_range cannot be used to opt-out a range whose iterator and sentinel satisfy sized_sentinel_for; disable_sized_sentinel_for must be used instead.
disable_sized_range cannot be specialized for array types or reference types.