From: Igor R (boost.lists_at_[hidden])
Date: 2008-06-15 12:14:30
> But I can't say the same things for non-const function which returns reference. <...> And also iterators are same as the index operator, not thread safe.
It seems that the only way to use such a container in the thread-safe
manner, is to perform all the necessary locking at some higher-level
of your design.
Besides the problem you mentioned, you've got another issue: usually
you wish to get not just "physical" thread-safety (meaning that your
container remains in a consistent state), but a "logical" one.
Consider the following code:
if (myVector_.size())
{
Element element = myVector_[0];
}
It doens't make sense that size() and operator[]() themselves are
"thread-safe", as between these calls the size might change. This
means that the user of your container has to lock it anyway. If so,
your internal locking appears to be useless overhead.