std::experimental::pmr::set_default_resource
Min standard notice:
Header: <experimental/memory_resource>
If r is not null, sets the default memory resource pointer to r; otherwise, sets the default memory resource pointer to new_delete_resource().
# Declarations
memory_resource* set_default_resource( memory_resource* r ) noexcept;
(library fundamentals TS)
# Return value
Returns the previous value of the default memory resource pointer.