[alg.req.ind.copy] (original) (raw)

23 Iterators library [iterators]

23.3 Iterator requirements [iterator.requirements]

23.3.7 Common algorithm requirements [alg.req]

23.3.7.3 Concept indirectly_­copyable [alg.req.ind.copy]

The indirectly_­copyable concept specifies the relationship between a indirectly_­readable type and a indirectly_­writable type between which values may be copied.

template<class In, class Out> concept indirectly_copyable = indirectly_readable && indirectly_writable<Out, iter_reference_t>;

The indirectly_­copyable_­storable concept augmentsindirectly_­copyable with additional requirements enabling the transfer to be performed through an intermediate object of theindirectly_­readable type's value type.

It also requires the capability to make copies of values.

template<class In, class Out> concept indirectly_copyable_storable = indirectly_copyable<In, Out> && indirectly_writable<Out, iter_value_t&> && indirectly_writable<Out, const iter_value_t&> && indirectly_writable<Out, iter_value_t&&> && indirectly_writable<Out, const iter_value_t&&> && copyable<iter_value_t> && constructible_from<iter_value_t, iter_reference_t> && assignable_from<iter_value_t&, iter_reference_t>;

Let i be a dereferenceable value of type In.

In and Out model indirectly_­copyable_­storable<In, Out>only if after the initialization of the object obj in

iter_value_t obj(*i);

obj is equal to the value previously denoted by *i.

Ifiter_­reference_­t<In> is an rvalue reference type, the resulting state of the value denoted by *i is valid but unspecified ([lib.types.movedfrom]).