CURLOPT_USERNAME(3) Library Functions Manual CURLOPT_USERNAME(3)
NAME
CURLOPT_USERNAME - username to use in authentication
SYNOPSIS
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_USERNAME,
char *username);
DESCRIPTION
Pass a char pointer as parameter, which should be pointing to the
null-terminated username to use for the transfer.
CURLOPT_USERNAME(3) sets the username to be used in protocol
authentication. You should not use this option together with the
(older) CURLOPT_USERPWD(3) option.
When using Kerberos V5 authentication with a Windows based server, you
should include the domain name in order for the server to successfully
obtain a Kerberos Ticket. If you do not then the initial part of the
authentication handshake may fail.
When using NTLM, the username can be specified without the domain name
should the server be part of a single domain and forest.
To include the domain name use either Down-Level Logon Name or UPN
(User Principal Name) formats. For example, EXAMPLEser and
user@example.com respectively.
Some HTTP servers (on Windows) support inclusion of the domain for
Basic authentication as well.
To specify the password and login options, along with the username, use
the CURLOPT_PASSWORD(3) and CURLOPT_LOGIN_OPTIONS(3) options.
The application does not have to keep the string around after setting
this option.
For some authentication methods (Negotiate, or NTLM when built to use
SSPI), setting it to a zero-length string ("") makes libcurl use an
implied ambient user decided by the environment. libcurl cannot
identify this user and may reuse an authenticated connection for a
later transfer on the same easy handle. If the ambient user changes
while that connection remains reusable, the later transfer can be
authenticated as the previous user. Applications must prevent such
reuse when changing ambient users.
DEFAULT
NULL
PROTOCOLS
This functionality affects all supported protocols
EXAMPLE
int main(void)
{
CURL *curl = curl_easy_init();
if(curl) {
CURLcode result;
curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/foo.bin");
curl_easy_setopt(curl, CURLOPT_USERNAME, "clark");
result = curl_easy_perform(curl);
curl_easy_cleanup(curl);
}
}
AVAILABILITY
Added in curl 7.19.1
RETURN VALUE
curl_easy_setopt(3) returns a CURLcode indicating success or error.
CURLE_OK (0) means everything was OK, non-zero means an error occurred,
see libcurl-errors(3).
SEE ALSO
CURLOPT_HTTPAUTH(3), CURLOPT_PASSWORD(3), CURLOPT_PROXYAUTH(3),
CURLOPT_USERPWD(3)
libcurl 2026-09-03 CURLOPT_USERNAME(3)
curl 8.22.0 - Generated Sat Sep 5 14:53:15 CDT 2026