:relfileprefix: ../../
[#boost-urls-optional]

= xref:boost.adoc[pass:[boost]]::xref:boost/urls.adoc[pass:[urls]]::optional



== Synopsis

Declared in header `<https://www.github.com/boostorg/url/blob/develop/include/boost/url/optional.hpp#L39[boost/url/optional.hpp,window=blank_]>`

[source,cpp,subs="verbatim,macros,-callouts"]
----
template<class T>
using optional = xref:boost.adoc[boost]::optional<T>;
----