Method Exchange

BeefRT/gperftools/src/malloc_hook.cc:162–174

// The code below is DEPRECATED.
template<typename PtrT>
PtrT AtomicPtr<PtrT>::Exchange(PtrT new_val) {
  base::subtle::GMemoryBarrier();  // Release semantics.
  // Depending on the system, NoBarrier_AtomicExchange(AtomicWord*)
  // may have been defined to return an AtomicWord, Atomic32, or
  // Atomic64.  We hide that implementation detail here with an
  // explicit cast.  This prevents MSVC 2005, at least, from complaining.
  PtrT old_val = reinterpret_cast<PtrT>(static_cast<AtomicWord>(
      base::subtle::NoBarrier_AtomicExchange(
          &data_,
          reinterpret_cast<AtomicWord>(new_val))));
  base::subtle::GMemoryBarrier();  // And acquire semantics.
  return old_val;
}

template<typename PtrT>
PtrT AtomicPtr<PtrT>::CompareAndSwap(PtrT old_val, PtrT new_val) {