std::indirectly_copyable_storable

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

The indirectly_copyable_storable concept specifies the relationship between an indirectly_readable type and an indirectly_writable type. In addition to indirectly_copyable, this concept specifies that the copy from the indirectly_readable type can be performed via an intermediate object.

Semantic requirements

In and Out model std::indirectly_copyable_storable<In, Out> only if given a dereferenceable value i of type In:

• After the definition std::iter_value_t<In> obj(*i);, obj is equal to the value previously denoted by *i, and
• if std::iter_reference_t<In> is an rvalue reference type, *i is placed in a valid but unspecified state after the initialization of obj.

Equality preservation

Expressions declared in requires expressions of the standard library concepts are required to be equality-preserving (except where stated otherwise).

See also