CURLOPT_TCP_KEEPCNT(3) Library Functions Manual CURLOPT_TCP_KEEPCNT(3)
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 con-
nection. 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) {
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 8.9.0
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_KEEPIDLE(3), CURLOPT_TCP_KEEP-
INTVL(3)
libcurl 2026-07-12 CURLOPT_TCP_KEEPCNT(3)
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