Defined in header <ranges> | ||
|---|---|---|
struct dangling; | (since C++20) |
dangling is a placeholder type and an empty class type, used together with the template aliases ranges::safe_iterator_t and ranges::safe_subrange_t.
When some constrain algorithms that usually return an iterator or a subrange of a Range take a particular rvalue Range argument that does not models exposition-only concept __ForwardingRange, dangling will be returned instead to avoid returning potentially dangling results.
constexpr dangling() noexcept = default; | (1) | |
template<class... Args>
constexpr dangling(Args&&...) noexcept { }
| (2) |
dangling is trivially default constructible.dangling can be constructed from arguments of arbitrary number and arbitrary non-void type. The construction does not have any side-effect itself. In other words, after replacing the type (e.g. an iterator type) in a well-formed non-aggregate initialization with dangling, the resulting initialization is also well-formed.
obtains iterator type or subrange type of a Range which also models __ForwardingRange (alias template) |
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