mirror of
https://github.com/moparisthebest/curl
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108 lines
3.7 KiB
Groff
108 lines
3.7 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) 1998 - 2019, 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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.\" **************************************************************************
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.\"
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.TH CURLMOPT_TIMERFUNCTION 3 "17 Jun 2014" "libcurl 7.37.0" "curl_multi_setopt options"
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.SH NAME
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CURLMOPT_TIMERFUNCTION \- set callback to receive timeout values
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.SH SYNOPSIS
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.nf
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#include <curl/curl.h>
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int timer_callback(CURLM *multi, /* multi handle */
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long timeout_ms, /* timeout in number of ms */
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void *userp); /* private callback pointer */
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CURLMcode curl_multi_setopt(CURLM *handle, CURLMOPT_TIMERFUNCTION, timer_callback);
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.SH DESCRIPTION
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Pass a pointer to your callback function, which should match the prototype
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shown above.
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Certain features, such as timeouts and retries, require you to call libcurl
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even when there is no activity on the file descriptors.
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Your callback function \fBtimer_callback\fP should install a non-repeating
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timer with an interval of \fBtimeout_ms\fP. When time that timer fires, call
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either \fIcurl_multi_socket_action(3)\fP or \fIcurl_multi_perform(3)\fP,
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depending on which interface you use.
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A \fBtimeout_ms\fP value of -1 passed to this callback means you should delete
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the timer. All other values are valid expire times in number of milliseconds.
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The \fBtimer_callback\fP will only be called when the timeout expire time is
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changed.
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The \fBuserp\fP pointer is set with \fICURLMOPT_TIMERDATA(3)\fP.
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The timer callback should return 0 on success, and -1 on error. This callback
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can be used instead of, or in addition to, \fIcurl_multi_timeout(3)\fP.
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\fBWARNING:\fP even if it feels tempting, avoid calling libcurl directly from
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within the callback itself when the \fBtimeout_ms\fP value is zero, since it
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risks triggering an unpleasant recursive behavior that immediately calls
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another call to the callback with a zero timeout...
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.SH DEFAULT
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NULL
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.SH PROTOCOLS
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All
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.SH EXAMPLE
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.nf
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static gboolean timeout_cb(gpointer user_data)
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{
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int running;
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if(user_data) {
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g_free(user_data);
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curl_multi_setopt(curl_handle, CURLMOPT_TIMERDATA, NULL);
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}
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curl_multi_socket_action(multi, CURL_SOCKET_TIMEOUT, 0, &running);
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return G_SOURCE_REMOVE;
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}
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static int timerfunc(CURLM *multi, long timeout_ms, void *userp)
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{
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guint *id = userp;
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if(id)
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g_source_remove(*id);
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/* -1 means we should just delete our timer. */
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if(timeout_ms == -1) {
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g_free(id);
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id = NULL;
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}
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else {
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if(!id)
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id = g_new(guint, 1);
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*id = g_timeout_add(timeout_ms, timeout_cb, id);
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}
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curl_multi_setopt(multi, CURLMOPT_TIMERDATA, id);
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return 0;
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}
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curl_multi_setopt(multi, CURLMOPT_TIMERFUNCTION, timerfunc);
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.fi
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.SH AVAILABILITY
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Added in 7.16.0
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.SH RETURN VALUE
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Returns CURLM_OK if the option is supported, and CURLM_UNKNOWN_OPTION if not.
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.SH "SEE ALSO"
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.BR CURLMOPT_TIMERDATA "(3), " CURLMOPT_SOCKETFUNCTION "(3), "
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