CURLOPT_TCP_KEEPINTVL(3) Library Functions Manual CURLOPT_TCP_KEEPINTVL(3)

CURLOPT_TCP_KEEPINTVL - TCP keep-alive interval

#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_TCP_KEEPINTVL, long interval);

Pass a long. Sets the interval, in seconds, to wait between sending keepalive probes. Not all operating systems support this option. (Added in 7.25.0)

The maximum value this accepts is 2147483648. Any larger value is capped to this amount.

60

This functionality affects tcp only

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    curl_easy_setopt(curl, CURLOPT_URL, "https://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);
    /* maximum number of keep-alive probes: 3 */
    curl_easy_setopt(curl, CURLOPT_TCP_KEEPCNT, 3L);
    curl_easy_perform(curl);
  }
}

Added in curl 7.25.0

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_TCP_KEEPALIVE(3), CURLOPT_TCP_KEEPCNT(3), CURLOPT_TCP_KEEPIDLE(3)

2025-02-08 libcurl