---
name: "CURLOPT_PROXY_SSLVERSION"
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_PROXY_SSLVERSION"
---

# CURLOPT\_PROXY\_SSLVERSION(3)

preferred HTTPS proxy TLS version

## NAME

CURLOPT\_PROXY\_SSLVERSION - preferred HTTPS proxy TLS version

## SYNOPSIS

```
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PROXY_SSLVERSION,
                          long version);
```

## DESCRIPTION

Pass a long as parameter to control which version of SSL/TLS to attempt to use when connecting to an HTTPS proxy.

Use one of the available defines for this purpose. The available options are:

- CURL\_SSLVERSION\_DEFAULT

  The default action. This attempts to figure out the remote SSL protocol version.

- CURL\_SSLVERSION\_TLSv1

  TLSv1.x

- CURL\_SSLVERSION\_TLSv1\_0

  TLSv1.0

- CURL\_SSLVERSION\_TLSv1\_1

  TLSv1.1

- CURL\_SSLVERSION\_TLSv1\_2

  TLSv1.2

- CURL\_SSLVERSION\_TLSv1\_3

  TLSv1.3 The maximum TLS version can be set by using *one* of the CURL\_SSLVERSION\_MAX\_ macros below. It is also possible to OR *one* of the CURL\_SSLVERSION\_ macros with *one* of the CURL\_SSLVERSION\_MAX\_ macros. The MAX macros are not supported for WolfSSL.

- CURL\_SSLVERSION\_MAX\_DEFAULT

  The flag defines the maximum supported TLS version as TLSv1.2, or the default value from the SSL library. (Added in 7.54.0)

- CURL\_SSLVERSION\_MAX\_TLSv1\_0

  The flag defines maximum supported TLS version as TLSv1.0. (Added in 7.54.0)

- CURL\_SSLVERSION\_MAX\_TLSv1\_1

  The flag defines maximum supported TLS version as TLSv1.1. (Added in 7.54.0)

- CURL\_SSLVERSION\_MAX\_TLSv1\_2

  The flag defines maximum supported TLS version as TLSv1.2. (Added in 7.54.0)

- CURL\_SSLVERSION\_MAX\_TLSv1\_3

  The flag defines maximum supported TLS version as TLSv1.3. (Added in 7.54.0)

  In versions of curl prior to 7.54 the CURL\_SSLVERSION\_TLS options were documented to allow *only* the specified TLS version, but behavior was inconsistent depending on the TLS library.

## DEFAULT

CURL\_SSLVERSION\_DEFAULT

## PROTOCOLS

All

## EXAMPLE

```
int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
    /* ask libcurl to use TLS version 1.0 or later */
    curl_easy_setopt(curl, CURLOPT_SSLVERSION, CURL_SSLVERSION_TLSv1);
    /* Perform the request */
    curl_easy_perform(curl);
  }
}
```

## AVAILABILITY

Added in 7.52.0

## RETURN VALUE

Returns CURLE\_OK if the option is supported, and CURLE\_UNKNOWN\_OPTION if not.

## SEE ALSO

[**CURLOPT\_HTTP\_VERSION**(3)](/CURLOPT_HTTP_VERSION/3.md), [**CURLOPT\_IPRESOLVE**(3)](/CURLOPT_IPRESOLVE/3.md), [**CURLOPT\_SSLVERSION**(3)](/CURLOPT_SSLVERSION/3.md), [**CURLOPT\_USE\_SSL**(3)](/CURLOPT_USE_SSL/3.md)