CURLOPT_SSL_SESSIONID_CACHE(3) Introduction to Library Functions

NAME

CURLOPT_SSL_SESSIONID_CACHE - use the SSL session-ID cache

SYNOPSIS

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_SESSIONID_CACHE,
long enabled);

DESCRIPTION

Pass a long set to 0 to disable libcurl's use of SSL session-ID
caching. Set this to 1 to enable it. By default all transfers are
done using the cache enabled. While nothing ever should get hurt by
attempting to reuse SSL session-IDs, there seem to be or have been
broken SSL implementations in the wild that may require you to
disable this in order for you to succeed.

DEFAULT

1

PROTOCOLS

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

All TLS backends support this option.

EXAMPLE

int main(void)
{
CURL *curl = curl_easy_init();
if(curl) {
CURLcode res;
curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
/* switch off session-id use */
curl_easy_setopt(curl, CURLOPT_SSL_SESSIONID_CACHE, 0L);
res = curl_easy_perform(curl);
curl_easy_cleanup(curl);
}
}

AVAILABILITY

Added in curl 7.16.0

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_DNS_CACHE_TIMEOUT(3), CURLOPT_MAXAGE_CONN(3),
CURLOPT_MAXLIFETIME_CONN(3), CURLOPT_SSLVERSION(3)

libcurl 2025-02-25 CURLOPT_SSL_SESSIONID_CACHE(3)