Method __add_weak

system/lib/libcxx/src/memory.cpp:51–51

void __shared_weak_count::__add_shared() noexcept { __shared_count::__add_shared(); }

void __shared_weak_count::__add_weak() noexcept { __libcpp_atomic_refcount_increment(__shared_weak_owners_); }

void __shared_weak_count::__release_shared() noexcept {
  if (__shared_count::__release_shared())