23 Iterators library [iterators]

23.5 Iterator adaptors [predef.iterators]

23.5.4 Common iterators [iterators.common]

23.5.4.4 Accessors [common.iter.access]

decltype(auto) operator*();
decltype(auto) operator*() const
  requires dereferenceable<const I>;

Preconditions: holds_alternative(v_).

Effects: Equivalent to: return *get(v_);

🔗

decltype(auto) operator->() const
  requires see below;

The expression in the requires clause is equivalent to:

indirectly_readable<const I> &&
(requires(const I& i) { i.operator->(); } ||
 is_reference_v<iter_reference_t<I>> ||
 constructible_from<iter_value_t<I>, iter_reference_t<I>>)

Preconditions: holds_alternative(v_).

Effects:

(5.1)
If I is a pointer type or if the expression get(v_).operator->() is well-formed, equivalent to: return get(v_);
(5.2)
Otherwise, if iter_reference_t is a reference type, equivalent to:
```
auto&& tmp = *get(v_);
return addressof(tmp);
```

(5.3)

Otherwise, equivalent to: return proxy(*get(v_)); where proxy is the exposition-only class:

class proxy {
  iter_value_t<I> keep_;
  proxy(iter_reference_t<I>&& x)
    : keep_(std::move(x)) {}
public:
  const iter_value_t<I>* operator->() const {
    return addressof(keep_);
  }
};