:relfileprefix: ../../../
[#boost-urls-grammar-is_rule-0a]

= xref:boost.adoc[pass:[boost]]::xref:boost/urls.adoc[pass:[urls]]::xref:boost/urls/grammar.adoc[pass:[grammar]]::is_rule



== Synopsis

Declared in header `<https://www.github.com/boostorg/url/blob/develop/include/boost/url/grammar/type_traits.hpp#L51[boost/url/grammar/type_traits.hpp,window=blank_]>`

[source,cpp,subs="verbatim,macros,-callouts"]
----
template<
    class T,
    class = void>
struct is_rule
    : xref:std.adoc[std]::false_type;
----



