1---
2c: Copyright (C) Daniel Stenberg, <daniel.se>, et al.
3SPDX-License-Identifier: curl
4Title: CURLOPT_TCP_KEEPALIVE
5Section: 3
6Source: libcurl
7See-also:
8  - CURLOPT_LOW_SPEED_LIMIT (3)
9  - CURLOPT_MAX_RECV_SPEED_LARGE (3)
10  - CURLOPT_TCP_KEEPIDLE (3)
11  - CURLOPT_TCP_KEEPINTVL (3)
12---
13
14# NAME
15
16CURLOPT_TCP_KEEPALIVE - TCP keep-alive probing
17
18# SYNOPSIS
19
20~~~c
21#include <curl/curl.h>
22
23CURLcode curl_easy_setopt(CURL *handle, CURLOPT_TCP_KEEPALIVE, long probe);
24~~~
25
26# DESCRIPTION
27
28Pass a long. If set to 1, TCP keepalive probes are used. The delay and
29frequency of these probes can be controlled by the
30CURLOPT_TCP_KEEPIDLE(3) and CURLOPT_TCP_KEEPINTVL(3) options,
31provided the operating system supports them. Set to 0 (default behavior) to
32disable keepalive probes
33
34# DEFAULT
35
360
37
38# PROTOCOLS
39
40All
41
42# EXAMPLE
43
44~~~c
45int main(void)
46{
47  CURL *curl = curl_easy_init();
48  if(curl) {
49    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
50
51    /* enable TCP keep-alive for this transfer */
52    curl_easy_setopt(curl, CURLOPT_TCP_KEEPALIVE, 1L);
53
54    /* keep-alive idle time to 120 seconds */
55    curl_easy_setopt(curl, CURLOPT_TCP_KEEPIDLE, 120L);
56
57    /* interval time between keep-alive probes: 60 seconds */
58    curl_easy_setopt(curl, CURLOPT_TCP_KEEPINTVL, 60L);
59
60    curl_easy_perform(curl);
61  }
62}
63~~~
64
65# AVAILABILITY
66
67Added in 7.25.0
68
69# RETURN VALUE
70
71Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
72