curl/docs/libcurl/opts/CURLOPT_TCP_KEEPINTVL.md
Daniel Stenberg e694c8284a
docs/libcurl/opts: clarify the return values
Expand a little.

- mention the type name of the return code
- avoid stating which exact return codes that might be returned, as that
  varies over time, builds and conditions
- avoid stating some always return OK
- refer to the manpage documenting all the return codes

Closes #15900
2025-01-02 17:13:33 +01:00

75 lines
1.5 KiB
Markdown

---
c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
SPDX-License-Identifier: curl
Title: CURLOPT_TCP_KEEPINTVL
Section: 3
Source: libcurl
See-also:
- CURLOPT_TCP_KEEPALIVE (3)
- CURLOPT_TCP_KEEPIDLE (3)
- CURLOPT_TCP_KEEPCNT (3)
Protocol:
- TCP
Added-in: 7.25.0
---
# NAME
CURLOPT_TCP_KEEPINTVL - TCP keep-alive interval
# SYNOPSIS
~~~c
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_TCP_KEEPINTVL, long interval);
~~~
# DESCRIPTION
Pass a long. Sets the interval, in seconds, to wait between sending keepalive
probes. Not all operating systems support this option. (Added in 7.25.0)
The maximum value this accepts is 2147483648. Any larger value is capped to
this amount.
# DEFAULT
60
# %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
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).