.\" generated by cd2nroff 0.1 from CURLOPT_SSL_EC_CURVES.md
.TH CURLOPT_SSL_EC_CURVES 3 "2024-11-18" libcurl
.SH NAME
CURLOPT_SSL_EC_CURVES \- key exchange curves
.SH SYNOPSIS
.nf
#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_EC_CURVES, char *alg_list);
.fi
.SH DESCRIPTION
Pass a string as parameter with a colon delimited list of (EC) algorithms. This
option defines the client\(aqs key exchange algorithms in the SSL handshake (if
the SSL backend libcurl is built to use supports it).
.SH DEFAULT
\&"", embedded in SSL backend
.SH PROTOCOLS
This functionality affects all TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc.

This option works only with the following TLS backends:
OpenSSL and wolfSSL
.SH EXAMPLE
.nf
int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode res;
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
    curl_easy_setopt(curl, CURLOPT_SSL_EC_CURVES, "X25519:P-521");
    res = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}
.fi
.SH AVAILABILITY
Added in curl 7.73.0
.SH RETURN VALUE
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
.SH SEE ALSO
.BR CURLOPT_SSL_CIPHER_LIST (3),
.BR CURLOPT_SSL_OPTIONS (3),
.BR CURLOPT_TLS13_CIPHERS (3)