Annotation of embedaddon/curl/docs/libcurl/opts/CURLOPT_UPKEEP_INTERVAL_MS.3, revision 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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