18 Language support library [language.support]

18.2 Common definitions [support.types]

18.2.1 Header <cstddef> synopsis [cstddef.syn]

namespace std {
  using ptrdiff_t = see below;
  using size_t = see below;
  using max_align_t = see below;
  using nullptr_t = decltype(nullptr);
}

#define NULL see below
#define offsetof(P, D) see below