争用共享变量的条件(Race condition for shared variable)

 我有一个double类型的共享变量。 这个变量将被两个线程访问。 一个线程永远只写变量，而另一个线程永远只读变量。 
 
 我仍然在这里获得比赛条件吗？ 如果是的话，C ++中有没有一种“简单”的方式来实现原子访问？ 如果读取数比写入数多得多，我如何有效地实现它？ 我需要将变量标记为volatile吗？ 
 
 编辑：确定“读取器”线程定期在批量数据上工作，并且新值的传播不是时间敏感的。 我可以声明写入器线程将写入的另一个临时变量，而不是实现复杂的互锁，而我没有很好的方法来测试。 然后，当阅读器完成一个批处理时，它可以将临时值自动传播到实际变量。 那会是无竞赛条件的吗？ 

I have a shared variable of type double. This variable will be accessed by two threads. One thread will ever only write the variable, whereas the other thread will ever only read the variable. 
 
Do I still get race condition here? If yes, is there an "easy" way in C++ to implement atomic access? How do I implement it efficiently if there is going to be much much more reads than writes? Do I need to mark the variable as volatile?
 
EDIT: OK the "reader" thread works periodically on batches of data and the propagation of the new value is not time-sensitive. Instead of implementing complicated interlocking that I have no good way to test, I can just declare another temp variable the writer thread will write to. Then when the reader is finished with one batch, it can atomically propagate the temp value to the actual variable. Would that be race-condition-free?

原文：https://stackoverflow.com/questions/10200147