I'm interested in doing something like(single thread update, multiple threads read banneedURLs):
atomic<bannedURLList*> bannedURLs;//global variable pointing to the currently used instance of struct
void updateList()
{
//no need for mutex because only 1 thread updates
bannedURLList* newList= new bannedURLList();
bannedURLList* oldList=bannedURLs;
new开发者_如何学CList->initialize();
bannedURLs=newList;// line must be after previous line, because list must be initialized before it is ready to be used
//while refcnt on the oldList >0 wait, then delete oldList;
}
reader threads do something like this:
{
bannedURLs->refCnt++;
//use bannedURLs
bannedURLs->refCnt--;
}
struct memeber refCnt is also atomic integer My question is how to prevent reordering of this 2 lines:
newList->initialize();
bannedURLs=newList;
Can it be done in std:: way?
Use bannedURLs.store(newList);
instead of bannedURLs=newList;
. Since you didn't pass a weak ordering specifier, this forces full ordering in the store.
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