[#BloombergLP-bslstl-IteratorUtil-insertDistance] = xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bslstl.adoc[bslstl]::xref:BloombergLP/bslstl/IteratorUtil.adoc[IteratorUtil]::insertDistance :relfileprefix: ../../../ :mrdocs: Return 0 if the (template parameter) type `t_INPUT_ITERATOR` is limited to the standard input‐iterator category, otherwise return the number of elements reachable from the specified `first` to (but not including) the specified `last`. This function has a constant‐time complexity if the iterator category of `t_INPUT_ITERATOR` is strictly a standard input iterator, or is a random access iterator, otherwise it is linear in the length of the range `[first .. last)]`. The behavior is undefined unless `last` is reachable from `first`. == Synopsis Declared in `<bslstl_iteratorutil.h>` [source,cpp,subs="verbatim,replacements,macros,-callouts"] ---- template< class t_INPUT_ITERATOR, class t_SENTINEL> static bsl::iterator_traits<t_INPUT_ITERATOR>::difference_type insertDistance( t_INPUT_ITERATOR const& first, t_SENTINEL const& last); ---- [.small]#Created with https://www.mrdocs.com[MrDocs]#