CURLOPT_TCP_KEEPINTVL(3) Introduction to Library Functions

NAME

CURLOPT_TCP_KEEPINTVL - TCP keep-alive interval

SYNOPSIS

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_TCP_KEEPINTVL, long interval);

DESCRIPTION

Pass a long. Sets the interval, in seconds, to wait between 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

EXAMPLE

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);
}
}

AVAILABILITY

Added in curl 7.25.0

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

libcurl 2026-01-08 CURLOPT_TCP_KEEPINTVL(3)