Is the C++ std::set thread-safe?

Question

I\'ve a question about the thread safety of std::set.

As far as I know I can iterate over a set and add/erase members and that doesn\'t invalidate the iterators.

Answer 1

Simple explanation: If thread A is moving iterators through the container, it's looking at container internals. If thread B modifies the container (even an operation that doesn't invalidate the iterator that A has), thread A can run into trouble because B is fooling with the container internals, possibly having them in a (temporarily) invalid state. This causes crashes in thread A.

The problem ISN'T the iterators themselves. It when they need the container's data structures in order to find the position that you get into trouble.

Simple as that.