# Parallel iteration

Member types `concurrent_set::range_type` and `concurrent_set::const_range_type` meet the ContainerRange requirements.

These types differ only in that the bounds for a `concurrent_set::const_range_type` are of type `concurrent_set::const_iterator`, whereas the bounds for a `concurrent_set::range_type` are of type `concurrent_set::iterator`.

## range member function

>     range_type range();

>     const_range_type range() const;

> Returns: a range object representing all elements in the container.