[#boost-urls-grammar-ref]
= xref:boost.adoc[boost]::xref:boost/urls.adoc[urls]::xref:boost/urls/grammar.adoc[grammar]::ref
:relfileprefix: ../../../
:mrdocs:


Return a reference to a character set

== Synopsis


Declared in `<https://www.github.com/boostorg/url/blob/develop/include/boost/url/grammar/charset.hpp#L251[boost/url/grammar/charset.hpp]>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<xref:boost/urls/grammar/CharSet.adoc[CharSet] CS>
constexpr
/* implementation-defined */::xref:boost/urls/grammar/implementation_defined/charset_ref.adoc[charset_ref]<CS>
xref:boost/urls/grammar/ref-02.adoc[ref](CS const& cs) noexcept
requires is_charset<CS>::value &&
    ! std::is_same<CS,
        implementation_defined::charset_ref<CS> >::value;
----

[.small]#xref:boost/urls/grammar/ref-02.adoc[_» more..._]#

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<xref:boost/urls/grammar/Rule.adoc[Rule] R>
constexpr
/* implementation-defined */::xref:boost/urls/grammar/implementation_defined/rule_ref.adoc[rule_ref]<R>
xref:boost/urls/grammar/ref-0e.adoc[ref](R const& r) noexcept
requires is_rule<R>::value &&
    ! std::is_same<R,
        implementation_defined::rule_ref<R> >::value;
----

[.small]#xref:boost/urls/grammar/ref-0e.adoc[_» more..._]#

== Description


This function returns a character set which    references the specified object. This is    used to reduce the number of bytes of    storage (`sizeof`) required by a combinator    when it stores a copy of the object.        Ownership of the object is not transferred;    the caller is responsible for ensuring the    lifetime of the object is extended until it    is no longer referenced. For best results,    `ref` should only be used with compile‐time    constants.



== Parameters


|===
| Name | Description

| *r*
| The rule to use


|===



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