:relfileprefix: ../../../ [#boost-urls-param-key] == xref:boost.adoc[pass:[boost]]::xref:boost/urls.adoc[pass:[urls]]::xref:boost/urls/param.adoc[pass:[param]]::key The key === Synopsis Declared in header `` [source,cpp,subs="verbatim,macros,-callouts"] ---- std::string key; ---- === Description For most usages, key comparisons are case-sensitive and duplicate keys in a query are possible. However, it is the authority that has final control over how the query is interpreted.