libcurl-url(3) Library Functions Manual libcurl-url(3)
NAME
libcurl-url - URL interface overview
DESCRIPTION
The URL interface provides functions for parsing and generating URLs.
INCLUDE
You still only include <curl/curl.h> in your code.
CREATE
Create a handle that holds URL info and resources with curl_url(3):
CURLU *h = curl_url();
CLEANUP
When done with it, clean it up with curl_url_cleanup(3)
curl_url_cleanup(h);
DUPLICATE
When you need a copy of a handle, just duplicate it with
curl_url_dup(3):
CURLU *nh = curl_url_dup(h);
PARSING
By setting a URL to the handle with curl_url_set(3), the URL is parsed
and stored in the handle. If the URL is not syntactically correct it re-
turns an error instead.
rc = curl_url_set(h, CURLUPART_URL,
"https://example.com:449/foo/bar?name=moo", 0);
The zero in the fourth argument is a bitmask for changing specific fea-
tures.
If successful, this stores the URL in its individual parts within the
handle.
REDIRECT
When a handle already contains info about a URL, setting a relative URL
makes it "redirect" to that.
rc = curl_url_set(h, CURLUPART_URL, "../test?another", 0);
GET URL
The CURLU handle represents a URL and you can easily extract that with
curl_url_get(3):
char *url;
rc = curl_url_get(h, CURLUPART_URL, &url, 0);
curl_free(url);
The zero in the fourth argument is a bitmask for changing specific fea-
tures.
GET PARTS
When a URL has been parsed or parts have been set, you can extract those
pieces from the handle at any time.
rc = curl_url_get(h, CURLUPART_FRAGMENT, &fragment, 0);
rc = curl_url_get(h, CURLUPART_HOST, &host, 0);
rc = curl_url_get(h, CURLUPART_PASSWORD, &password, 0);
rc = curl_url_get(h, CURLUPART_PATH, &path, 0);
rc = curl_url_get(h, CURLUPART_PORT, &port, 0);
rc = curl_url_get(h, CURLUPART_QUERY, &query, 0);
rc = curl_url_get(h, CURLUPART_SCHEME, &scheme, 0);
rc = curl_url_get(h, CURLUPART_USER, &user, 0);
rc = curl_url_get(h, CURLUPART_ZONEID, &zoneid, 0);
Extracted parts are not URL decoded unless the user also asks for it
with the CURLU_URLDECODE flag set in the fourth bitmask argument.
Remember to free the returned string with curl_free(3) when you are done
with it.
SET PARTS
A user set individual URL parts, either after having parsed a full URL
or instead of parsing such.
rc = curl_url_set(urlp, CURLUPART_FRAGMENT, "anchor", 0);
rc = curl_url_set(urlp, CURLUPART_HOST, "www.example.com", 0);
rc = curl_url_set(urlp, CURLUPART_PASSWORD, "doe", 0);
rc = curl_url_set(urlp, CURLUPART_PATH, "/index.html", 0);
rc = curl_url_set(urlp, CURLUPART_PORT, "443", 0);
rc = curl_url_set(urlp, CURLUPART_QUERY, "name=john", 0);
rc = curl_url_set(urlp, CURLUPART_SCHEME, "https", 0);
rc = curl_url_set(urlp, CURLUPART_USER, "john", 0);
rc = curl_url_set(urlp, CURLUPART_ZONEID, "eth0", 0);
Set parts are not URL encoded unless the user asks for it with the
CURLU_URLENCODE flag.
CURLU_APPENDQUERY
An application can append a string to the right end of the query part
with the CURLU_APPENDQUERY flag to curl_url_set(3).
Imagine a handle that holds the URL "https://example.com/?shoes=2". An
application can then add the string "hat=1" to the query part like this:
rc = curl_url_set(urlp, CURLUPART_QUERY, "hat=1", CURLU_APPENDQUERY);
It notices the lack of an ampersand (&) separator and injects one, and
the handle's full URL then equals "https://example.com/?shoes=2&hat=1".
The appended string can of course also get URL encoded on add, and if
asked to URL encode, the encoding process skips the '=' character. For
example, append "candy=N&N" to what we already have, and URL encode it
to deal with the ampersand in the data:
rc = curl_url_set(urlp, CURLUPART_QUERY, "candy=N&N",
CURLU_APPENDQUERY | CURLU_URLENCODE);
Now the URL looks like
https://example.com/?shoes=2&hat=1&candy=N%26N
NOTES
A URL with a literal IPv6 address can be parsed even when IPv6 support
is not enabled.
SEE ALSO
CURLOPT_URL(3), curl_url(3), curl_url_cleanup(3), curl_url_dup(3),
curl_url_get(3), curl_url_set(3), curl_url_strerror(3)
libcurl 2026-07-12 libcurl-url(3)
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