85 lines
2.8 KiB
Groff
85 lines
2.8 KiB
Groff
.\" **************************************************************************
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.\" * _ _ ____ _
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.\" * Project ___| | | | _ \| |
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.\" * / __| | | | |_) | |
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.\" * | (__| |_| | _ <| |___
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.\" * \___|\___/|_| \_\_____|
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.\" *
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.\" * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
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.\" *
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.\" * This software is licensed as described in the file COPYING, which
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.\" * you should have received as part of this distribution. The terms
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.\" * are also available at https://curl.se/docs/copyright.html.
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.\" *
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.\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell
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.\" * copies of the Software, and permit persons to whom the Software is
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.\" * furnished to do so, under the terms of the COPYING file.
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.\" *
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.\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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.\" * KIND, either express or implied.
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.\" *
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.\" * SPDX-License-Identifier: curl
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.\" *
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.\" **************************************************************************
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.\"
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.TH curl_easy_upkeep 3 "31 Oct 2018" "libcurl" "libcurl"
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.SH NAME
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curl_easy_upkeep - Perform any connection upkeep checks.
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.SH SYNOPSIS
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.nf
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#include <curl/curl.h>
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CURLcode curl_easy_upkeep(CURL *handle);
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.fi
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.SH DESCRIPTION
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Some protocols have "connection upkeep" mechanisms. These mechanisms usually
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send some traffic on existing connections in order to keep them alive; this
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can prevent connections from being closed due to overzealous firewalls, for
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example.
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Currently the only protocol with a connection upkeep mechanism is HTTP/2: when
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the connection upkeep interval is exceeded and \fIcurl_easy_upkeep(3)\fP
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is called, an HTTP/2 PING frame is sent on the connection.
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This function must be explicitly called in order to perform the upkeep work.
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The connection upkeep interval is set with
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\fICURLOPT_UPKEEP_INTERVAL_MS(3)\fP.
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.SH EXAMPLE
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.nf
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int main(void)
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{
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CURL *curl = curl_easy_init();
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if(curl) {
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/* Make a connection to an HTTP/2 server. */
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curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
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/* Set the interval to 30000ms / 30s */
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curl_easy_setopt(curl, CURLOPT_UPKEEP_INTERVAL_MS, 30000L);
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curl_easy_perform(curl);
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/* Perform more work here. */
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/* While the connection is being held open, curl_easy_upkeep() can be
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called. If curl_easy_upkeep() is called and the time since the last
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upkeep exceeds the interval, then an HTTP/2 PING is sent. */
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curl_easy_upkeep(curl);
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/* Perform more work here. */
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/* always cleanup */
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curl_easy_cleanup(curl);
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}
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}
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.fi
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.SH AVAILABILITY
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Added in 7.62.0.
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.SH RETURN VALUE
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On success, returns \fBCURLE_OK\fP.
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On failure, returns the appropriate error code.
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.SH SEE ALSO
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.BR CURLOPT_TCP_KEEPALIVE "(3), "
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.BR CURLOPT_TCP_KEEPIDLE "(3), "
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