:relfileprefix: ../../../
[#ACA41F159E9D7F37AE4AA64BF8F80F3692054398]

= Function url_base::set_scheme

pass:v,q[Set the scheme]


== Synopsis

Declared in header `</boost/url/url_base.hpp#L242[boost/url/url_base.hpp,window=blank_]>`

[source,cpp,subs="verbatim,macros,-callouts"]
----
xref:boost/urls/url_base.adoc[url_base]&
set_scheme(string_view s);
----

== Description

pass:v,q[The scheme is set to the specified] pass:v,q[string, which must contain a valid]
pass:v,q[scheme without any trailing colon]
pass:v,q[(':').]
pass:v,q[Note that schemes are case-insensitive,]
pass:v,q[and the canonical form is lowercased.]

=== Example
[,cpp]
----
assert( url( "http://www.example.com" ).set_scheme( "https" ).scheme_id() == scheme::https );
----

=== Complexity
pass:v,q[Linear in `this->size() + s.size()`.]

=== Exception Safety
pass:v,q[Strong guarantee.]
pass:v,q[Calls to allocate may throw.]
pass:v,q[Exceptions thrown on invalid input.]

=== BNF
[,cpp]
----
scheme        = ALPHA *( ALPHA / DIGIT / "+" / "-" / "." )
----

=== Specification

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



== Return Value

* `` 


== Parameters

|===
| Name | Type 

| *s*
| `string_view`

|===