---
name: "CURLOPT_USERNAME"
section: "3"
platform: "macos"
package: "curl"
version: "166.0.0.0.1"
release: "macOS 26.5"
platforms: ["linux", "macos"]
url: "https://new.carta.tech/CURLOPT_USERNAME"
---

# CURLOPT\_USERNAME(3)

user name to use in authentication

## NAME

CURLOPT\_USERNAME - user name 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 user name to use for the transfer.

*[CURLOPT\_USERNAME(3)](/CURLOPT_USERNAME/3.md)* sets the user name to be used in protocol authentication. You should not use this option together with the (older) *[CURLOPT\_USERPWD(3)](/CURLOPT_USERPWD/3.md)* 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 user name can be specified simply as the user name 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 user name, use the *[CURLOPT\_PASSWORD(3)](/CURLOPT_PASSWORD/3.md)* and *[CURLOPT\_LOGIN\_OPTIONS(3)](/CURLOPT_LOGIN_OPTIONS/3.md)* options.

The application does not have to keep the string around after setting this option.

## DEFAULT

blank

## PROTOCOLS

Most

## EXAMPLE

```
int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode res;
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/foo.bin");
    curl_easy_setopt(curl, CURLOPT_USERNAME, "clark");
    res = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}
```

## AVAILABILITY

Added in 7.19.1

## RETURN VALUE

Returns CURLE\_OK if the option is supported, CURLE\_UNKNOWN\_OPTION if not, or CURLE\_OUT\_OF\_MEMORY if there was insufficient heap space.

## SEE ALSO

[**CURLOPT\_HTTPAUTH**(3)](/CURLOPT_HTTPAUTH/3.md), [**CURLOPT\_PASSWORD**(3)](/CURLOPT_PASSWORD/3.md), [**CURLOPT\_PROXYAUTH**(3)](/CURLOPT_PROXYAUTH/3.md), [**CURLOPT\_USERPWD**(3)](/CURLOPT_USERPWD/3.md)