bsl::set::upper_bound

Return an iterator providing non‐modifiable access to the first (i.e., ordered least) value_type object in this set greater than the specified key, and the past‐the‐end iterator if this set does not contain a value_type object greater‐than key. Note that this function returns the last position before which a value_type object equivalent to key could be inserted into the ordered sequence maintained by this set, while preserving its ordering.