---
name: "CURLOPT_TCP_KEEPINTVL"
section: "3"
platform: "linux"
package: "curl"
version: "8.23.0-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux", "macos"]
url: "https://new.carta.tech/CURLOPT_TCP_KEEPINTVL"
---

# CURLOPT\_TCP\_KEEPINTVL(3)

TCP keep-alive interval

## 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) {
    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);
  }
}
```

## AVAILABILITY

Added in curl 7.25.0

## RETURN VALUE

*[curl\_easy\_setopt(3)](/curl_easy_setopt/3.md)* returns a CURLcode indicating success or error.

CURLE\_OK (0) means everything was OK, non-zero means an error occurred, see *[libcurl-errors(3)](/libcurl-errors/3.md)*.

## SEE ALSO

[**CURLOPT\_TCP\_KEEPALIVE**(3)](/CURLOPT_TCP_KEEPALIVE/3.md), [**CURLOPT\_TCP\_KEEPCNT**(3)](/CURLOPT_TCP_KEEPCNT/3.md), [**CURLOPT\_TCP\_KEEPIDLE**(3)](/CURLOPT_TCP_KEEPIDLE/3.md)