e3fe020089
Remove the PROTOCOLS section from the source files completely and instead generate them based on the header data in the curldown files. It also generates TLS backend information for options marked for TLS as protocol. Closes #13175
81 lines
1.8 KiB
Markdown
81 lines
1.8 KiB
Markdown
---
|
|
c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
|
|
SPDX-License-Identifier: curl
|
|
Title: CURLOPT_UPKEEP_INTERVAL_MS
|
|
Section: 3
|
|
Source: libcurl
|
|
See-also:
|
|
- CURLOPT_TCP_KEEPALIVE (3)
|
|
Protocol:
|
|
- All
|
|
---
|
|
|
|
# NAME
|
|
|
|
CURLOPT_UPKEEP_INTERVAL_MS - connection upkeep interval
|
|
|
|
# SYNOPSIS
|
|
|
|
~~~c
|
|
#include <curl/curl.h>
|
|
|
|
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_UPKEEP_INTERVAL_MS,
|
|
long upkeep_interval_ms);
|
|
~~~
|
|
|
|
# DESCRIPTION
|
|
|
|
Some protocols have "connection upkeep" mechanisms. These mechanisms usually
|
|
send some traffic on existing connections in order to keep them alive; this
|
|
can prevent connections from being closed due to overzealous firewalls, for
|
|
example.
|
|
|
|
The user needs to explicitly call curl_easy_upkeep(3) in order to
|
|
perform the upkeep work.
|
|
|
|
Currently the only protocol with a connection upkeep mechanism is HTTP/2: when
|
|
the connection upkeep interval is exceeded and curl_easy_upkeep(3)
|
|
is called, an HTTP/2 PING frame is sent on the connection.
|
|
|
|
# DEFAULT
|
|
|
|
CURL_UPKEEP_INTERVAL_DEFAULT (currently defined as 60000L, which is 60 seconds)
|
|
|
|
# EXAMPLE
|
|
|
|
~~~c
|
|
int main(void)
|
|
{
|
|
CURL *curl = curl_easy_init();
|
|
if(curl) {
|
|
/* Make a connection to an HTTP/2 server. */
|
|
curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
|
|
|
|
/* Set the interval to 30000ms / 30s */
|
|
curl_easy_setopt(curl, CURLOPT_UPKEEP_INTERVAL_MS, 30000L);
|
|
|
|
curl_easy_perform(curl);
|
|
|
|
/* Perform more work here. */
|
|
|
|
/* While the connection is being held open, curl_easy_upkeep() can be
|
|
called. If curl_easy_upkeep() is called and the time since the last
|
|
upkeep exceeds the interval, then an HTTP/2 PING is sent. */
|
|
curl_easy_upkeep(curl);
|
|
|
|
/* Perform more work here. */
|
|
|
|
/* always cleanup */
|
|
curl_easy_cleanup(curl);
|
|
}
|
|
}
|
|
~~~
|
|
|
|
# AVAILABILITY
|
|
|
|
Added in 7.62.0
|
|
|
|
# RETURN VALUE
|
|
|
|
Returns CURLE_OK
|