[#boost-urls-url_view-2constructor]
= xref:boost.adoc[boost]::xref:boost/urls.adoc[urls]::xref:boost/urls/url_view.adoc[url_view]::url_view
:relfileprefix: ../../../
:mrdocs:


Constructor

== Synopsis


Declared in `<https://www.github.com/boostorg/url/blob/develop/include/boost/url/url_view.hpp#L89[boost/url/url_view.hpp]>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
explicit
xref:boost/urls/url_view/2constructor-00.adoc[url_view](/* implementation-defined */::url_impl const& impl) noexcept;
----

[.small]#xref:boost/urls/url_view/2constructor-00.adoc[_» more..._]#

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
xref:boost/urls/url_view/2constructor-0c.adoc[url_view]() noexcept;
----

[.small]#xref:boost/urls/url_view/2constructor-0c.adoc[_» more..._]#

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
xref:boost/urls/url_view/2constructor-025.adoc[url_view](core::string_view s);
----

[.small]#xref:boost/urls/url_view/2constructor-025.adoc[_» more..._]#

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<class String>
requires std::is_convertible<
                String,
                core::string_view
                    >::value &&
            !std::is_convertible<
                String*,
                url_view_base*
                    >::value && std::is_convertible<
                String,
                core::string_view
                    >::value &&
            !std::is_convertible<
                String*,
                url_view_base*
                    >::value
xref:boost/urls/url_view/2constructor-00.adoc[url_view](String const& s);
----

[.small]#xref:boost/urls/url_view/2constructor-00.adoc[_» more..._]#

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
xref:boost/urls/url_view/2constructor-024.adoc[url_view](xref:boost/urls/url_view.adoc[url_view] const& other) noexcept;
----

[.small]#xref:boost/urls/url_view/2constructor-024.adoc[_» more..._]#

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
xref:boost/urls/url_view/2constructor-0a.adoc[url_view](xref:boost/urls/url_view_base.adoc[url_view_base] const& other) noexcept;
----

[.small]#xref:boost/urls/url_view/2constructor-0a.adoc[_» more..._]#

== Description


Default constructed views refer to        a string with zero length, which        always remains valid. This matches        the grammar for a relative‐ref with        an empty path and no query or        fragment.


=== Example

[,cpp]
----
url_view u;
----

=== Postconditions

[,cpp]
----
this->empty() == true
----

=== Complexity

Constant.


=== Exception Safety

Throws nothing.


=== BNF

[,cpp]
----
relative-ref  = relative-part [ "?" query ] [ "#" fragment ]
----

=== Specification

link:https://datatracker.ietf.org/doc/html/rfc3986#section-4.2[4.2. Relative Reference (rfc3986)]



== Exceptions


|===
| Name | Thrown on

| `system_error`
| The input failed to parse correctly.


|===

== Parameters


|===
| Name | Description

| *s*
| The string to parse.


|===



[.small]#Created with https://www.mrdocs.com[MrDocs]#