---
c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
SPDX-License-Identifier: curl
Title: CURLOPT_TCP_KEEPCNT
Section: 3
Source: libcurl
See-also:
  - CURLOPT_TCP_KEEPALIVE (3)
  - CURLOPT_TCP_KEEPIDLE (3)
  - CURLOPT_TCP_KEEPINTVL (3)
Protocol:
  - TCP
Added-in: 8.9.0
---

# NAME

CURLOPT_TCP_KEEPCNT - Maximum number of TCP keep-alive probes

# SYNOPSIS

~~~c
#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%

# EXAMPLE

~~~c
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%

# RETURN VALUE

Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.