a607f8a20c
Windows does not support using select() for sleeping without a dummy socket. Instead use Windows' Sleep() and sleep for 100ms which is the minimum suggested value in the curl_multi_fdset() doc. Prior to this change the multi examples would exit prematurely since select() would error instead of sleeping when called without an fd. Reported-by: Johan Lantz Bug: http://curl.haxx.se/mail/lib-2014-11/0221.html
140 lines
3.8 KiB
C
140 lines
3.8 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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/* This is a very simple example using the multi interface. */
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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 a HTTP file.
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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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CURLM *multi_handle;
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int still_running; /* keep number of running handles */
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curl_global_init(CURL_GLOBAL_DEFAULT);
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http_handle = curl_easy_init();
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/* set the options (I left out a few, you'll get the point anyway) */
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curl_easy_setopt(http_handle, CURLOPT_URL, "http://www.example.com/");
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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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/* 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) we call
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select(0, ...), which is basically equal to sleeping the timeout. On
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Windows we can't sleep via select without a dummy socket and instead
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we Sleep() for 100ms which is the minimum suggested value in the
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curl_multi_fdset() doc. */
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#ifdef _WIN32
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if(maxfd == -1) {
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Sleep(100);
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rc = 0;
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}
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else
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#endif
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{
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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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still_running = 0;
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printf("select() returns error, this is badness\n");
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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_remove_handle(multi_handle, http_handle);
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curl_easy_cleanup(http_handle);
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curl_multi_cleanup(multi_handle);
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curl_global_cleanup();
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return 0;
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}
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