---
name: "CURLOPT_TLSAUTH_USERNAME"
section: "3"
platform: "linux"
package: "curl"
version: "8.23.0-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux", "macos"]
url: "https://new.carta.tech/CURLOPT_TLSAUTH_USERNAME"
---

# CURLOPT\_TLSAUTH\_USERNAME(3)

username to use for TLS authentication

## NAME

CURLOPT\_TLSAUTH\_USERNAME - username to use for TLS authentication

## SYNOPSIS

```
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_TLSAUTH_USERNAME, char *user);
```

## DESCRIPTION

Deprecated option. It serves no purpose anymore.

Pass a char pointer as parameter, which should point to the null-terminated username to use for the TLS authentication method specified with the *[CURLOPT\_TLSAUTH\_TYPE(3)](/CURLOPT_TLSAUTH_TYPE/3.md)* option. Requires that the *[CURLOPT\_TLSAUTH\_PASSWORD(3)](/CURLOPT_TLSAUTH_PASSWORD/3.md)* option also be set.

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

Using this option multiple times makes the last set string override the previous ones. Set it to NULL to disable its use again.

This feature relies on TLS-SRP which does not work with TLS 1.3.

## DEFAULT

NULL

## DEPRECATED

This option was deprecated in 8.22.0.

## PROTOCOLS

This functionality affects  all TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc. only

This option works only with the following TLS backends: GnuTLS and OpenSSL

## EXAMPLE

```
int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode result;
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
    curl_easy_setopt(curl, CURLOPT_TLSAUTH_TYPE, "SRP");
    curl_easy_setopt(curl, CURLOPT_TLSAUTH_USERNAME, "user");
    curl_easy_setopt(curl, CURLOPT_TLSAUTH_PASSWORD, "secret");
    result = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}
```

## AVAILABILITY

Added in curl 7.21.4

## RETURN VALUE

*[curl\_easy\_setopt(3)](/curl_easy_setopt/3.md)* returns a CURLcode indicating success or error.

CURLE\_OK (0) means everything was OK, non-zero means an error occurred, see *[libcurl-errors(3)](/libcurl-errors/3.md)*.

## SEE ALSO

[**CURLOPT\_TLSAUTH\_PASSWORD**(3)](/CURLOPT_TLSAUTH_PASSWORD/3.md), [**CURLOPT\_TLSAUTH\_TYPE**(3)](/CURLOPT_TLSAUTH_TYPE/3.md)