1 template<class Lock>
 2 class lock_guard{
 3 public:
 4     explicit lock_guard(Lock& lock){
 5         lock.lock();
 6     }
 7     ~lock_guard(){
 8         lock.unlock();
 9     }
10     lock_guard(const lock_guard&) = delete;
11     lock_guard& operator = (const lock_guard&) = delete;
12 };
13 
14 class TTASLock{
15 private:
16     atomic<bool> state;
17 public:
18     void lock(){
19         while (true){
20             while (state.load()){};
21             if (!state.exchange(true, std::memory_order_relaxed))
22                 return;
23         }
24     }
25     void unlock(){
26         state.store(false);
27     }
28 };