Return an iterator providing non-modifiable access to the first value_type object in the sequence of value_type objects maintained by this unordered multiset, or the end iterator if this unordered multiset is empty.
Declared in <bslstl_unorderedmultiset.h>
unordered_multiset<KEY, HASH, EQUAL, ALLOCATOR>::const_iterator
cbegin() const noexcept;