CURLOPT_MAXLIFETIME_CONN - Man Page

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_MAXLIFETIME_CONN,
                          long maxlifetime);

Pass a long as parameter containing maxlifetime - the maximum time in seconds, since the creation of the connection, that you allow an existing connection to have to be considered for reuse for this request.

libcurl features a connection cache that holds previously used connections. When a new request is to be done, libcurl considers any connection that matches for reuse. The CURLOPT_MAXLIFETIME_CONN(3) limit prevents libcurl from trying too old connections for reuse. This can be used for client-side load balancing. If a connection is found in the cache that is older than this set maxlifetime, it is instead marked for closure.

If set to 0, this behavior is disabled: all connections are eligible for reuse.

24 hours (since 8.17.0). Before that, the default was 0 seconds (i.e., disabled)

This functionality affects all supported protocols

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");

    /* only allow each connection to be reused for 30 seconds */
    curl_easy_setopt(curl, CURLOPT_MAXLIFETIME_CONN, 30L);

    curl_easy_perform(curl);
  }
}

Added in curl 7.80.0

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).

CURLOPT_FORBID_REUSE(3), CURLOPT_FRESH_CONNECT(3), CURLOPT_MAXAGE_CONN(3), CURLOPT_TIMEOUT(3)

curl_easy_setopt(3), CURLOPT_FORBID_REUSE(3), CURLOPT_FRESH_CONNECT(3), CURLOPT_MAXAGE_CONN(3), CURLOPT_SSL_SESSIONID_CACHE(3), libcurl-security(3), libcurl-symbols(3).