:relfileprefix: ../../
[#boost-urls-scheme]

= xref:boost.adoc[pass:[boost]]::xref:boost/urls.adoc[pass:[urls]]::scheme


Identifies a known URL scheme


== Synopsis

Declared in header `<https://www.github.com/boostorg/url/blob/develop/include/boost/url/scheme.hpp#L33[boost/url/scheme.hpp,window=blank_]>`

[source,cpp,subs="verbatim,macros,-callouts"]
----
enum scheme : unsigned short;
----

== Members
[,cols=2]
|===
|Name |Description
|xref:boost/urls/scheme/none.adoc[`pass:v[none]`] |
Indicates that no scheme is present

|xref:boost/urls/scheme/unknown.adoc[`pass:v[unknown]`] |
Indicates the scheme is not a well-known scheme

|xref:boost/urls/scheme/ftp.adoc[`pass:v[ftp]`] |
File Transfer Protocol (FTP)

|xref:boost/urls/scheme/file.adoc[`pass:v[file]`] |
File URI Scheme

|xref:boost/urls/scheme/http.adoc[`pass:v[http]`] |
The Hypertext Transfer Protocol URI Scheme

|xref:boost/urls/scheme/https.adoc[`pass:v[https]`] |
The Secure Hypertext Transfer Protocol URI Scheme

|xref:boost/urls/scheme/ws.adoc[`pass:v[ws]`] |
The WebSocket URI Scheme

|xref:boost/urls/scheme/wss.adoc[`pass:v[wss]`] |
The Secure WebSocket URI Scheme

|===

== Description


=== Specification

* link:https://datatracker.ietf.org/doc/html/rfc3986#section-3.1[3.1. Scheme (rfc3986)]