boost::urls::url::url Constructor Synopsis url() noexcept; explicit url(core::string_view s); url(url&& u) noexcept; url(url_view_base const& u); url(url const& u); Description Default constructed urls contain a zero-length string. This matches the grammar for a relative-ref with an empty path and no query or fragment. url u; this->empty() == true Constant. Throws nothing. relative-ref = relative-part [ "?" query ] [ "#" fragment ] 4.2. Relative Reference (rfc3986) Exceptions Name Thrown on The input does not contain a valid url. `u.size() > max_size()`. Parameters Name Description s The string to parse. u The url to move from.