Atomic and nonatomic

Because the difference lies in thread safety, it can be regarded as a multi-threaded interview question

atomic Atomic operations , It is also called thread safety

nonatomic It's non atomic operation , The essence is that you must lock to be thread safe

if (!atomic) {
    oldValue = *slot;
    *slot = newValue;
} else {
    spinlock_t& slotlock = PropertyLocks[slot];
    slotlock.lock();
    oldValue = *slot;
    *slot = newValue;        
    slotlock.unlock();
}

In fact, there is no need to explain too much , Just look at the source code , This will determine whether it is atomic, If yes , Just add a lock , Only one thread can modify at a time

Not recommended for use atomic, Because even normal calls will be locked , This code efficiency is very low , Lock where you need it l