curl-w32/docs/libcurl/opts/CURLOPT_TCP_KEEPALIVE.md

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---
c: Copyright (C) Daniel Stenberg, <daniel.se>, et al.
SPDX-License-Identifier: curl
Title: CURLOPT_TCP_KEEPALIVE
Section: 3
Source: libcurl
See-also:
- CURLOPT_LOW_SPEED_LIMIT (3)
- CURLOPT_MAX_RECV_SPEED_LARGE (3)
- CURLOPT_TCP_KEEPIDLE (3)
- CURLOPT_TCP_KEEPINTVL (3)
---
# NAME
CURLOPT_TCP_KEEPALIVE - TCP keep-alive probing
# SYNOPSIS
~~~c
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_TCP_KEEPALIVE, long probe);
~~~
# DESCRIPTION
Pass a long. If set to 1, TCP keepalive probes are used. The delay and
frequency of these probes can be controlled by the
CURLOPT_TCP_KEEPIDLE(3) and CURLOPT_TCP_KEEPINTVL(3) options,
provided the operating system supports them. Set to 0 (default behavior) to
disable keepalive probes
# DEFAULT
0
# PROTOCOLS
All
# 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);
/* 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);
curl_easy_perform(curl);
}
}
~~~
# AVAILABILITY
Added in 7.25.0
# RETURN VALUE
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.