Method CompareAndSwap

be/src/common/atomic.h:104–106

Atomically compare 'old_val' to 'value_' and set 'value_' to 'new_val' and return true if they compared equal, otherwise return false (and do no updates), with "barrier" memory-ordering semantic. That is, atomically performs: if (value_ == old_val) { value_ = new_val; return true; } return false;

  ///  }
  ///  return false;
  ALWAYS_INLINE bool CompareAndSwap(T old_val, T new_val) {
    return base::subtle::Barrier_CompareAndSwap(&value_, old_val, new_val) == old_val;
  }

  /// Store 'new_val' and return the previous value. Implies a Release memory barrier
  /// (i.e. the same as Store()).