26 Containers library [containers]

26.4 Associative containers [associative]

26.4.7 Class template multiset [multiset]

26.4.7.3 multiset specialized algorithms [multiset.special]

template<class Key, class Compare, class Allocator> void swap(multiset<Key, Compare, Allocator>& x, multiset<Key, Compare, Allocator>& y) noexcept(noexcept(x.swap(y)));
Effects: As if by x.swap(y).