Standard C++ Library Reference ISO/IEC (VERSION3)

Both return an iterator that designates the first element remaining beyond any elements
removed, or end() if no such element exists.
The third member removes the elements with sort keys in the range
[lower_bound(keyval), upper_bound(keyval)). It returns the number of
elements it removes.
The member functions never throw an exception.
multimap::find
iterator find(const Key& keyval);
const_iterator find(const Key& keyval) const;
The member function returns an iterator that designates the earliest element in the controlled
sequence whose sort key has equivalent ordering to keyval. If no such element exists, the
function returns end().
multimap::get_allocator
Alloc get_allocator() const;
The member function returns the stored allocator object.
multimap::insert
iterator insert(const value_type& val);
iterator insert(iterator where, const value_type& val);
template<class InIt>
void insert(InIt first, InIt last);
The first member function inserts the element val in the controlled sequence, then returns the
iterator that designates the inserted element. The second member function returns
insert(val), using where as a starting place within the controlled sequence to search for
the insertion point. (Insertion can occur in amortized constant time, instead of logarithmic time,
if the insertion point immediately precedes or follows where.) The third member function
inserts the sequence of element values, for each where in the range [first, last), by
calling insert(*where).
If an exception is thrown during the insertion of a single element, the container is left unaltered
and the exception is rethrown. If an exception is thrown during the insertion of multiple
elements, the container is left in a stable but unspecified state and the exception is rethrown.