Is there any way to check if an iterator is valid?

Question

For two threads manipulating a container map for example, what the correct way to test whether an iterator still valid (for performance reason) ?
Or would be of only in

Answer 1

std::maps are not at all thread-safe. You'll end up with much worse problems than invalidated iterators, if you have more than one thread at a time modifying the same map. I don't even think you have a guarantee that you can read anything out of a map while it's being modified by another thread.

Some pages on the STL and threading:

• MSDN
• SGI
• GCC