Annotation of embedaddon/curl/docs/libcurl/opts/CURLOPT_UPKEEP_INTERVAL_MS.3, revision 1.1.1.1
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23: .TH CURLOPT_UPKEEP_INTERVAL_MS 3 "31 Oct 2018" "libcurl 7.62.0" "curl_easy_setopt options"
24: .SH NAME
25: CURLOPT_UPKEEP_INTERVAL_MS \- connection upkeep interval
26: .SH SYNOPSIS
27: #include <curl/curl.h>
28:
29: CURLcode curl_easy_setopt(CURL *handle, CURLOPT_UPKEEP_INTERVAL_MS, long upkeep_interval_ms);
30: .SH DESCRIPTION
31: Some protocols have "connection upkeep" mechanisms. These mechanisms usually
32: send some traffic on existing connections in order to keep them alive; this
33: can prevent connections from being closed due to overzealous firewalls, for
34: example.
35:
36: The user needs to explicitly call \fIcurl_easy_upkeep(3)\fP in order to
37: perform the upkeep work.
38:
39: Currently the only protocol with a connection upkeep mechanism is HTTP/2: when
40: the connection upkeep interval is exceeded and \fIcurl_easy_upkeep(3)\fP
41: is called, an HTTP/2 PING frame is sent on the connection.
42:
43: .SH DEFAULT
44: CURL_UPKEEP_INTERVAL_DEFAULT (currently defined as 60000L, which is 60 seconds)
45: .SH EXAMPLE
46: .nf
47: CURL *curl = curl_easy_init();
48: if(curl) {
49: /* Make a connection to an HTTP/2 server. */
50: curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
51:
52: /* Set the interval to 30000ms / 30s */
53: curl_easy_setopt(curl, CURLOPT_UPKEEP_INTERVAL_MS, 30000L);
54:
55: curl_easy_perform(curl);
56:
57: /* Perform more work here. */
58:
59: /* While the connection is being held open, curl_easy_upkeep() can be
60: called. If curl_easy_upkeep() is called and the time since the last
61: upkeep exceeds the interval, then an HTTP/2 PING is sent. */
62: curl_easy_upkeep(curl);
63:
64: /* Perform more work here. */
65:
66: /* always cleanup */
67: curl_easy_cleanup(curl);
68: }
69: .fi
70: .SH AVAILABILITY
71: Added in 7.62.0
72: .SH RETURN VALUE
73: Returns CURLE_OK
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