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      1 /***************************************************************************
      2  *                                  _   _ ____  _
      3  *  Project                     ___| | | |  _ \| |
      4  *                             / __| | | | |_) | |
      5  *                            | (__| |_| |  _ <| |___
      6  *                             \___|\___/|_| \_\_____|
      7  *
      8  * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel (at) haxx.se>, et al.
      9  *
     10  * This software is licensed as described in the file COPYING, which
     11  * you should have received as part of this distribution. The terms
     12  * are also available at https://curl.haxx.se/docs/copyright.html.
     13  *
     14  * You may opt to use, copy, modify, merge, publish, distribute and/or sell
     15  * copies of the Software, and permit persons to whom the Software is
     16  * furnished to do so, under the terms of the COPYING file.
     17  *
     18  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
     19  * KIND, either express or implied.
     20  *
     21  ***************************************************************************/
     22 /* <DESC>
     23  * Download many files in parallel, in the same thread.
     24  * </DESC>
     25  */
     26 
     27 #include <errno.h>
     28 #include <stdlib.h>
     29 #include <string.h>
     30 #ifndef WIN32
     31 #  include <unistd.h>
     32 #endif
     33 #include <curl/curl.h>
     34 
     35 static const char *urls[] = {
     36   "https://www.microsoft.com",
     37   "https://opensource.org",
     38   "https://www.google.com",
     39   "https://www.yahoo.com",
     40   "https://www.ibm.com",
     41   "https://www.mysql.com",
     42   "https://www.oracle.com",
     43   "https://www.ripe.net",
     44   "https://www.iana.org",
     45   "https://www.amazon.com",
     46   "https://www.netcraft.com",
     47   "https://www.heise.de",
     48   "https://www.chip.de",
     49   "https://www.ca.com",
     50   "https://www.cnet.com",
     51   "https://www.mozilla.org",
     52   "https://www.cnn.com",
     53   "https://www.wikipedia.org",
     54   "https://www.dell.com",
     55   "https://www.hp.com",
     56   "https://www.cert.org",
     57   "https://www.mit.edu",
     58   "https://www.nist.gov",
     59   "https://www.ebay.com",
     60   "https://www.playstation.com",
     61   "https://www.uefa.com",
     62   "https://www.ieee.org",
     63   "https://www.apple.com",
     64   "https://www.symantec.com",
     65   "https://www.zdnet.com",
     66   "https://www.fujitsu.com/global/",
     67   "https://www.supermicro.com",
     68   "https://www.hotmail.com",
     69   "https://www.ietf.org",
     70   "https://www.bbc.co.uk",
     71   "https://news.google.com",
     72   "https://www.foxnews.com",
     73   "https://www.msn.com",
     74   "https://www.wired.com",
     75   "https://www.sky.com",
     76   "https://www.usatoday.com",
     77   "https://www.cbs.com",
     78   "https://www.nbc.com/",
     79   "https://slashdot.org",
     80   "https://www.informationweek.com",
     81   "https://apache.org",
     82   "https://www.un.org",
     83 };
     84 
     85 #define MAX_PARALLEL 10 /* number of simultaneous transfers */
     86 #define NUM_URLS sizeof(urls)/sizeof(char *)
     87 
     88 static size_t write_cb(char *data, size_t n, size_t l, void *userp)
     89 {
     90   /* take care of the data here, ignored in this example */
     91   (void)data;
     92   (void)userp;
     93   return n*l;
     94 }
     95 
     96 static void add_transfer(CURLM *cm, int i)
     97 {
     98   CURL *eh = curl_easy_init();
     99   curl_easy_setopt(eh, CURLOPT_WRITEFUNCTION, write_cb);
    100   curl_easy_setopt(eh, CURLOPT_URL, urls[i]);
    101   curl_easy_setopt(eh, CURLOPT_PRIVATE, urls[i]);
    102   curl_multi_add_handle(cm, eh);
    103 }
    104 
    105 int main(void)
    106 {
    107   CURLM *cm;
    108   CURLMsg *msg;
    109   unsigned int transfers = 0;
    110   int msgs_left = -1;
    111   int still_alive = 1;
    112 
    113   curl_global_init(CURL_GLOBAL_ALL);
    114   cm = curl_multi_init();
    115 
    116   /* Limit the amount of simultaneous connections curl should allow: */
    117   curl_multi_setopt(cm, CURLMOPT_MAXCONNECTS, (long)MAX_PARALLEL);
    118 
    119   for(transfers = 0; transfers < MAX_PARALLEL; transfers++)
    120     add_transfer(cm, transfers);
    121 
    122   do {
    123     curl_multi_perform(cm, &still_alive);
    124 
    125     while((msg = curl_multi_info_read(cm, &msgs_left))) {
    126       if(msg->msg == CURLMSG_DONE) {
    127         char *url;
    128         CURL *e = msg->easy_handle;
    129         curl_easy_getinfo(msg->easy_handle, CURLINFO_PRIVATE, &url);
    130         fprintf(stderr, "R: %d - %s <%s>\n",
    131                 msg->data.result, curl_easy_strerror(msg->data.result), url);
    132         curl_multi_remove_handle(cm, e);
    133         curl_easy_cleanup(e);
    134       }
    135       else {
    136         fprintf(stderr, "E: CURLMsg (%d)\n", msg->msg);
    137       }
    138       if(transfers < NUM_URLS)
    139         add_transfer(cm, transfers++);
    140     }
    141     if(still_alive)
    142       curl_multi_wait(cm, NULL, 0, 1000, NULL);
    143 
    144   } while(still_alive || (transfers < NUM_URLS));
    145 
    146   curl_multi_cleanup(cm);
    147   curl_global_cleanup();
    148 
    149   return EXIT_SUCCESS;
    150 }
    151