...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
boost::container::pmr::operator==
// In header: <boost/container/pmr/polymorphic_allocator.hpp> template<typename T1, typename T2> bool operator==(const polymorphic_allocator< T1 > & a, const polymorphic_allocator< T2 > & b);