std::ranges::rbegin

Returns an iterator to the last element of the argument.

If T is an array type and std::remove_all_extents_t<std::remove_reference_t<T>> is incomplete, then the call to ranges::rbegin is ill-formed, no diagnostic required.

If the argument is an lvalue or ranges::enable_borrowed_range<std::remove_cv_t<T>> is true, then a call to ranges::rbegin is expression-equivalent to:

1. decay-copy(t.rbegin())(until C++23)auto(t.rbegin())(since C++23), if that expression is valid and its type models std::input_or_output_iterator.
2. Otherwise, decay-copy(rbegin(t))(until C++23)auto(rbegin(t))(since C++23), if T is a class or enumeration type, that expression is valid and its type models std::input_or_output_iterator, where the meaning of rbegin is established as if by performing argument-dependent lookup only.
3. Otherwise, std::make_reverse_iterator(ranges::end(t)) if both ranges::begin(t) and ranges::end(t) are valid expressions, have the same type, and that type models std::bidirectional_iterator.

In all other cases, a call to ranges::rbegin is ill-formed, which can result in substitution failure when ranges::rbegin(t) appears in the immediate context of a template instantiation.

Customization point objects

The name ranges::rbegin denotes a customization point object, which is a const function object of a literal