23 Iterators library [iterators]

23.5 Iterator adaptors [predef.iterators]

23.5.4 Common iterators [iterators.common]

23.5.4.3 Constructors and conversions [common.iter.const]

constexpr common_iterator(I i);
Effects: Initializes v_­ as if by v_­{in_­place_­type<I>, std​::​move(i)}.
constexpr common_iterator(S s);
Effects: Initializes v_­ as if by v_­{in_­place_­type<S>, std​::​move(s)}.
template<class I2, class S2> requires convertible_to<const I2&, I> && convertible_to<const S2&, S> constexpr common_iterator(const common_iterator<I2, S2>& x);
Expects: x.v_­.valueless_­by_­exception() is false.
Effects: Initializes v_­ as if by v_­{in_­place_­index<i>, get<i>(x.v_­)}, where i is x.v_­.index().
template<class I2, class S2> requires convertible_to<const I2&, I> && convertible_to<const S2&, S> && assignable_from<I&, const I2&> && assignable_from<S&, const S2&> common_iterator& operator=(const common_iterator<I2, S2>& x);
Expects: x.v_­.valueless_­by_­exception() is false.
Effects: Equivalent to:
  • If v_­.index() == x.v_­.index(), then get<i>(v_­) = get<i>(x.v_­).
  • Otherwise, v_­.emplace<i>(get<i>(x.v_­)).
where i is x.v_­.index().
Returns: *this