A class or pointer type
meets the requirements of an output iterator
if X meets the Cpp17Iterator requirements ([iterator.iterators])
and the expressions in Table 86
are valid and have the indicated semantics.
Table 86: Cpp17OutputIterator requirements (in addition to Cpp17Iterator) [tab:outputiterator]
*r = o
result is not used
Remarks: After this operation r is not required to be dereferenceable.