CURLOPT_TCP_KEEPIDLE − set TCP keep-alive idle time wait
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_TCP_KEEPIDLE, long delay);
Pass a long. Sets the delay, in seconds, that the operating system will wait while the connection is idle before sending keepalive probes. Not all operating systems support this option.
CURL *curl = curl_easy_init();
curl_easy_setopt(curl, CURLOPT_URL, "http://example.com");
/* enable TCP keep-alive for this transfer */
curl_easy_setopt(curl, CURLOPT_TCP_KEEPALIVE, 1L);
/* set keep-alive idle time to 120 seconds */
curl_easy_setopt(curl, CURLOPT_TCP_KEEPIDLE, 120L);
/* interval time between keep-alive probes: 60 seconds */
curl_easy_setopt(curl, CURLOPT_TCP_KEEPINTVL, 60L);
Added in 7.25.0
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.