22 Containers library [containers]

22.2 Container requirements [container.requirements]

22.2.7 Unordered associative containers [unord.req]

22.2.7.2 Exception safety guarantees [unord.req.except]

For unordered associative containers, no clear() function throws an exception.
erase(k) does not throw an exception unless that exception is thrown by the container's Hash or Pred object (if any).
For unordered associative containers, if an exception is thrown by any operation other than the container's hash function from within an insert or emplace function inserting a single element, the insertion has no effect.
For unordered associative containers, no swap function throws an exception unless that exception is thrown by the swap of the container's Hash or Pred object (if any).
For unordered associative containers, if an exception is thrown from within a rehash() function other than by the container's hash function or comparison function, the rehash() function has no effect.