:relfileprefix: ../../../
[#boost-urls-url_base-set_scheme]

== xref:boost.adoc[pass:[boost]]::xref:boost/urls.adoc[pass:[urls]]::xref:boost/urls/url_base.adoc[pass:[url_base]]::set_scheme


Set the scheme


=== Synopsis

Declared in header `<https://www.github.com/boostorg/url/blob/develop/include/boost/url/url_base.hpp#L244[boost/url/url_base.hpp,window=blank_]>`

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

=== Description


The scheme is set to the specified
string, which must contain a valid
scheme without any trailing colon
(':').
Note that schemes are case-insensitive,
and the canonical form is lowercased.
[,cpp]
----
assert( url( "http://www.example.com" ).set_scheme( "https" ).scheme_id() == scheme::https );
----

=== Linear in `this-&gt;size() + s.size()`.

=== Strong guarantee.

Calls to allocate may throw.
Exceptions thrown on invalid input.
[,cpp]
----
scheme        = ALPHA *( ALPHA / DIGIT / "+" / "-" / "." )
----

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



=== Exceptions

|===
| Name | Thrown on

| ``s``
| 
contains an invalid scheme.

|===



=== Parameters

|===
| Name | Description 

| *s*
| 
The scheme to set.

|===




=== See Also


xref:boost/urls/url_base/remove_scheme.adoc[remove_scheme]
.



