:relfileprefix: ../../
[#B0FB7E975E9642424B8AA33E9BE07A779B3D780D]

= unreserved_chars

pass:v,q[The unreserved character set]


== Synopsis

Declared in header `</boost/url/rfc/unreserved_chars.hpp#L44[boost/url/rfc/unreserved_chars.hpp,window=blank_]>`

[source,cpp,subs="verbatim,macros,-callouts"]
----
constexpr
const xref:boost/urls/grammar.adoc[grammar]::xref:boost/urls/grammar/lut_chars.adoc[lut_chars] unreserved_chars;
----

== Description


=== Example
pass:v,q[Character sets are used with rules and] pass:v,q[the functions]
xref:boost/urls/grammar/find_if.adoc[grammar::find_if]
pass:v,q[and]
xref:boost/urls/grammar/find_if_not.adoc[grammar::find_if_not.]
[,cpp]
----
system::result< decode_view > rv = grammar::parse( "Program%20Files", pct_encoded_rule( unreserved_chars ) );
----

=== BNF
[,cpp]
----
unreserved    = ALPHA / DIGIT / "-" / "." / "_" / "~"
----

=== Specification

* link:https://datatracker.ietf.org/doc/html/rfc3986#section-2.3[2.3. Unreserved Characters (rfc3986)]