如果迭代器未因插入而无效，则使用std :: find和C :: insert（）线程安全

Question

Suppose I have a container C whose iterators are not invalidated upon C.insert(), can I safely perform a std::find() on the container while a concurrent insert() is being performed? That is, am I guaranteed to find a matching element or C::end(), ignoring the fact that the inserted element may match but std::find() gives me C::end()?

Answer 1

No. Although iterators are not invalidated by your mutating operation, it is still a mutating operation, and none of the standard containers are defined to be safe to read in one thread while a mutating operation is taking place in another. Remember that there are still "innards" to your container, all manner of internal state, which may be involved in both operations.