1---
2c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
3SPDX-License-Identifier: curl
4Title: CURLOPT_TCP_KEEPINTVL
5Section: 3
6Source: libcurl
7See-also:
8  - CURLOPT_TCP_KEEPALIVE (3)
9  - CURLOPT_TCP_KEEPIDLE (3)
10  - CURLOPT_TCP_KEEPCNT (3)
11Protocol:
12  - TCP
13Added-in: 7.25.0
14---
15
16# NAME
17
18CURLOPT_TCP_KEEPINTVL - TCP keep-alive interval
19
20# SYNOPSIS
21
22~~~c
23#include <curl/curl.h>
24
25CURLcode curl_easy_setopt(CURL *handle, CURLOPT_TCP_KEEPINTVL, long interval);
26~~~
27
28# DESCRIPTION
29
30Pass a long. Sets the interval, in seconds, to wait between sending keepalive
31probes. Not all operating systems support this option. (Added in 7.25.0)
32
33The maximum value this accepts is 2147483648. Any larger value is capped to
34this amount.
35
36# DEFAULT
37
3860
39
40# %PROTOCOLS%
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    /* set 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    /* maximum number of keep-alive probes: 3 */
61    curl_easy_setopt(curl, CURLOPT_TCP_KEEPCNT, 3L);
62
63    curl_easy_perform(curl);
64  }
65}
66~~~
67
68# %AVAILABILITY%
69
70# RETURN VALUE
71
72Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
73