c++ - mix atomic and non atomic variables and caches -


let's have piece of code correct (i hope @ least) :

std::atomic<int> a; std::atomic<bool> ready{false}; void threada() {     a.store(666, std::memory_order_relaxed);     ready.store(true, std::memory_order_release); }  void threadb() {     while(!ready.load(std::memory_order_acquire));     process(a.load(std::memory_order_relaxed)); }

my question : in case using int a; instead of std::atomic<int> a;, correct well? or there problem of cache flushing / invalidation?

whether or not idea, example, code fine..

you may replace atomic type of a regular int (or type matter).
c++ standard supports case following phrase (§ 1.10.1-6):

certain library calls synchronize other library calls performed thread. example, atomic store-release synchronizes load-acquire takes value store

since threadb loads value of ready stored threada (it waiting in loop), synchronizes-with relationship established. therefore, a.load() observes memory effects of a.store(). way a.store() happens-before a.load()


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