## 使用锁 ```c++ std::mutex mutex; mutex.lock(); // 更新最大值 mutex.unlock(); ``` ## 原子变量 ```c++ template<typename T> void update_maximum(std::atomic<T>& maximum_value, T const& value) noexcept { T prev_value = maximum_value; while(prev_value <value && !maximum_value.compare_exchange_weak(prev_value, value)); } ```