cb13fad733
Prior to this change when no file descriptors were ready on platforms other than Windows the multi examples would sleep whatever was in timeout, which may or may not have been less than the minimum recommended value [1] of 100ms. [1]: http://curl.haxx.se/libcurl/c/curl_multi_fdset.html
141 lines
3.9 KiB
C
141 lines
3.9 KiB
C
/***************************************************************************
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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 - 2011, 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 http://curl.haxx.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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#include <stdio.h>
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#include <string.h>
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/* somewhat unix-specific */
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#include <sys/time.h>
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#include <unistd.h>
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/* curl stuff */
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#include <curl/curl.h>
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/*
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* Simply download two HTTP files!
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*/
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int main(void)
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{
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CURL *http_handle;
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CURL *http_handle2;
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CURLM *multi_handle;
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int still_running; /* keep number of running handles */
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http_handle = curl_easy_init();
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http_handle2 = curl_easy_init();
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/* set options */
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curl_easy_setopt(http_handle, CURLOPT_URL, "http://www.example.com/");
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/* set options */
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curl_easy_setopt(http_handle2, CURLOPT_URL, "http://localhost/");
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/* init a multi stack */
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multi_handle = curl_multi_init();
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/* add the individual transfers */
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curl_multi_add_handle(multi_handle, http_handle);
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curl_multi_add_handle(multi_handle, http_handle2);
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/* we start some action by calling perform right away */
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curl_multi_perform(multi_handle, &still_running);
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do {
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struct timeval timeout;
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int rc; /* select() return code */
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CURLMcode mc; /* curl_multi_fdset() return code */
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fd_set fdread;
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fd_set fdwrite;
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fd_set fdexcep;
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int maxfd = -1;
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long curl_timeo = -1;
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FD_ZERO(&fdread);
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FD_ZERO(&fdwrite);
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FD_ZERO(&fdexcep);
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/* set a suitable timeout to play around with */
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timeout.tv_sec = 1;
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timeout.tv_usec = 0;
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curl_multi_timeout(multi_handle, &curl_timeo);
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if(curl_timeo >= 0) {
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timeout.tv_sec = curl_timeo / 1000;
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if(timeout.tv_sec > 1)
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timeout.tv_sec = 1;
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else
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timeout.tv_usec = (curl_timeo % 1000) * 1000;
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}
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/* get file descriptors from the transfers */
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mc = curl_multi_fdset(multi_handle, &fdread, &fdwrite, &fdexcep, &maxfd);
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if(mc != CURLM_OK)
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{
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fprintf(stderr, "curl_multi_fdset() failed, code %d.\n", mc);
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break;
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}
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/* On success the value of maxfd is guaranteed to be >= -1. We call
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select(maxfd + 1, ...); specially in case of (maxfd == -1) there are
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no fds ready yet so we call select(0, ...) --or Sleep() on Windows--
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to sleep 100ms, which is the minimum suggested value in the
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curl_multi_fdset() doc. */
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if(maxfd == -1) {
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#ifdef _WIN32
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Sleep(100);
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rc = 0;
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#else
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/* Portable sleep for platforms other than Windows. */
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struct timeval wait = { 0, 100 * 1000 }; /* 100ms */
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rc = select(0, NULL, NULL, NULL, &wait);
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#endif
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}
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else {
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/* Note that on some platforms 'timeout' may be modified by select().
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If you need access to the original value save a copy beforehand. */
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rc = select(maxfd+1, &fdread, &fdwrite, &fdexcep, &timeout);
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}
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switch(rc) {
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case -1:
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/* select error */
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break;
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case 0:
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default:
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/* timeout or readable/writable sockets */
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curl_multi_perform(multi_handle, &still_running);
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break;
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}
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} while(still_running);
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curl_multi_cleanup(multi_handle);
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curl_easy_cleanup(http_handle);
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curl_easy_cleanup(http_handle2);
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return 0;
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}
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