:relfileprefix: ../../
[#FFACD68C814DE5D7F43C18FDCC5B1F3548CD63AB]

= Function resolve

pass:v,q[Resolve a URL reference against a base URL]


== Synopsis

Declared in header `</boost/url/url_base.hpp#L2744[boost/url/url_base.hpp,window=blank_]>`

[source,cpp,subs="verbatim,macros,-callouts"]
----
result<void>
resolve(
    const xref:boost/urls/url_view_base.adoc[url_view_base]& base,
    const xref:boost/urls/url_view_base.adoc[url_view_base]& ref,
    xref:boost/urls/url_base.adoc[url_base]& dest);
----

== Description

pass:v,q[This function attempts to resolve a URL] pass:v,q[reference `ref` against the base URL `base`]
pass:v,q[in a manner similar to that of a web browser]
pass:v,q[resolving an anchor tag.]
pass:v,q[The base URL must satisfy the]
pass:v,q[URI]
pass:v,q[grammar. In other words, it must contain]
pass:v,q[a scheme.]
pass:v,q[Relative references are only usable when]
pass:v,q[in the context of a base absolute URI.]
pass:v,q[This process of resolving a relative]
pass:v,q[reference]
pass:v,q[within the context of]
pass:v,q[a]
pass:v,q[base]
pass:v,q[URI is defined in detail]
pass:v,q[in rfc3986 (see below).]
pass:v,q[The resolution process works as if the]
pass:v,q[relative reference is appended to the base]
pass:v,q[URI and the result is normalized.]
pass:v,q[Given the input base URL, this function]
pass:v,q[resolves the relative reference]
pass:v,q[as if performing the following steps:]

* pass:v,q[Ensure the base URI has at least a scheme]

* pass:v,q[Normalizing the reference path]

* pass:v,q[Merge base and reference paths]

* pass:v,q[Normalize the merged path]
pass:v,q[This function places the result of the]
pass:v,q[resolution into `dest`, which can be]
pass:v,q[any of the url containers that inherit]
pass:v,q[from]
xref:boost/urls/url_base.adoc[url_base.]
pass:v,q[If an error occurs, the contents of]
pass:v,q[`dest` is unspecified and `ec` is set.]

=== Example
[,cpp]
----
url dest;
system::error_code ec;

resolve("/one/two/three", "four", dest, ec);
assert( dest.str() == "/one/two/four" );

resolve("http://example.com/", "/one", dest, ec);
assert( dest.str() == "http://example.com/one" );

resolve("http://example.com/one", "/two", dest, ec);
assert( dest.str() == "http://example.com/two" );

resolve("http://a/b/c/d;p?q", "g#s", dest, ec);
assert( dest.str() == "http://a/b/c/g#s" );
----

=== BNF
[,cpp]
----
absolute-URI  = scheme ":" hier-part [ "?" query ]
----

=== Exception Safety
pass:v,q[Basic guarantee.]
pass:v,q[Calls to allocate may throw.]

=== Specification
link:https://datatracker.ietf.org/doc/html/rfc3986#section-5[5. Reference Resolution (rfc3986)]



== Return Value

* `result` 


== Parameters

|===
| Name | Type 

| *base*
| ``

| *ref*
| ``

| *dest*
| ``

|===