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

# CURLOPT\_TCP\_KEEPCNT(3)

Maximum number of TCP keep-alive probes

## NAME

CURLOPT\_TCP\_KEEPCNT - Maximum number of TCP keep-alive probes

## SYNOPSIS

```
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_TCP_KEEPCNT, long cnt);
```

## DESCRIPTION

Pass a long. Sets the number of probes to send before dropping the connection. Not all operating systems support this option. (Added in 8.9.0)

The maximum value this option accepts is INT\_MAX or whatever your system allows. Any larger value is capped to this amount.

## DEFAULT

9

## 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 8.9.0

## 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\_KEEPIDLE**(3)](/CURLOPT_TCP_KEEPIDLE/3.md), [**CURLOPT\_TCP\_KEEPINTVL**(3)](/CURLOPT_TCP_KEEPINTVL/3.md)