20 Memory management library [mem]

20.4 Memory resources [mem.res]

20.4.3 Class template polymorphic_allocator [mem.poly.allocator.class] Constructors [mem.poly.allocator.ctor]

polymorphic_allocator() noexcept;
Effects: Sets memory_rsrc to get_default_resource().
polymorphic_allocator(memory_resource* r);
Preconditions: r is non-null.
Effects: Sets memory_rsrc to r.
Throws: Nothing.
[Note 1: 
This constructor provides an implicit conversion from memory_resource*.
— end note]
template<class U> polymorphic_allocator(const polymorphic_allocator<U>& other) noexcept;
Effects: Sets memory_rsrc to other.resource().