CURLOPT_TCP_KEEPIDLE(3)

CURLOPT_TCP_KEEPIDLE3

Tcp keep-alive idle time wait

Usage

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

Overview

Pass a long. Sets the delay, in seconds, to wait while the connection is idle before sending keepalive probes. Not all operating systems support this option.

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

Default

60

Protocols

This functionality affects tcp only

Examples

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode result;
    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);
    result = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}

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).

Releases

7 releases since Debian 8 (Jessie); the text changed 6 times.

  1. 8
  2. 9
  3. 10
  4. 11
  5. 12
  6. 13
  7. Arch

Availability

Added in curl 7.25.0

From curl 8.23.0-1 in Arch Linux 2026-11-01. Parsed by carta from the page's man source.