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    1: /***************************************************************************
    2:  *                                  _   _ ____  _
    3:  *  Project                     ___| | | |  _ \| |
    4:  *                             / __| | | | |_) | |
    5:  *                            | (__| |_| |  _ <| |___
    6:  *                             \___|\___/|_| \_\_____|
    7:  *
    8:  * Copyright (C) 1998 - 2018, Daniel Stenberg, <daniel@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:  * multi interface code doing two parallel HTTP transfers
   24:  * </DESC>
   25:  */
   26: #include <stdio.h>
   27: #include <string.h>
   28: 
   29: /* somewhat unix-specific */
   30: #include <sys/time.h>
   31: #include <unistd.h>
   32: 
   33: /* curl stuff */
   34: #include <curl/curl.h>
   35: 
   36: /*
   37:  * Simply download two HTTP files!
   38:  */
   39: int main(void)
   40: {
   41:   CURL *http_handle;
   42:   CURL *http_handle2;
   43:   CURLM *multi_handle;
   44: 
   45:   int still_running = 0; /* keep number of running handles */
   46: 
   47:   http_handle = curl_easy_init();
   48:   http_handle2 = curl_easy_init();
   49: 
   50:   /* set options */
   51:   curl_easy_setopt(http_handle, CURLOPT_URL, "https://www.example.com/");
   52: 
   53:   /* set options */
   54:   curl_easy_setopt(http_handle2, CURLOPT_URL, "http://localhost/");
   55: 
   56:   /* init a multi stack */
   57:   multi_handle = curl_multi_init();
   58: 
   59:   /* add the individual transfers */
   60:   curl_multi_add_handle(multi_handle, http_handle);
   61:   curl_multi_add_handle(multi_handle, http_handle2);
   62: 
   63:   /* we start some action by calling perform right away */
   64:   curl_multi_perform(multi_handle, &still_running);
   65: 
   66:   while(still_running) {
   67:     struct timeval timeout;
   68:     int rc; /* select() return code */
   69:     CURLMcode mc; /* curl_multi_fdset() return code */
   70: 
   71:     fd_set fdread;
   72:     fd_set fdwrite;
   73:     fd_set fdexcep;
   74:     int maxfd = -1;
   75: 
   76:     long curl_timeo = -1;
   77: 
   78:     FD_ZERO(&fdread);
   79:     FD_ZERO(&fdwrite);
   80:     FD_ZERO(&fdexcep);
   81: 
   82:     /* set a suitable timeout to play around with */
   83:     timeout.tv_sec = 1;
   84:     timeout.tv_usec = 0;
   85: 
   86:     curl_multi_timeout(multi_handle, &curl_timeo);
   87:     if(curl_timeo >= 0) {
   88:       timeout.tv_sec = curl_timeo / 1000;
   89:       if(timeout.tv_sec > 1)
   90:         timeout.tv_sec = 1;
   91:       else
   92:         timeout.tv_usec = (curl_timeo % 1000) * 1000;
   93:     }
   94: 
   95:     /* get file descriptors from the transfers */
   96:     mc = curl_multi_fdset(multi_handle, &fdread, &fdwrite, &fdexcep, &maxfd);
   97: 
   98:     if(mc != CURLM_OK) {
   99:       fprintf(stderr, "curl_multi_fdset() failed, code %d.\n", mc);
  100:       break;
  101:     }
  102: 
  103:     /* On success the value of maxfd is guaranteed to be >= -1. We call
  104:        select(maxfd + 1, ...); specially in case of (maxfd == -1) there are
  105:        no fds ready yet so we call select(0, ...) --or Sleep() on Windows--
  106:        to sleep 100ms, which is the minimum suggested value in the
  107:        curl_multi_fdset() doc. */
  108: 
  109:     if(maxfd == -1) {
  110: #ifdef _WIN32
  111:       Sleep(100);
  112:       rc = 0;
  113: #else
  114:       /* Portable sleep for platforms other than Windows. */
  115:       struct timeval wait = { 0, 100 * 1000 }; /* 100ms */
  116:       rc = select(0, NULL, NULL, NULL, &wait);
  117: #endif
  118:     }
  119:     else {
  120:       /* Note that on some platforms 'timeout' may be modified by select().
  121:          If you need access to the original value save a copy beforehand. */
  122:       rc = select(maxfd + 1, &fdread, &fdwrite, &fdexcep, &timeout);
  123:     }
  124: 
  125:     switch(rc) {
  126:     case -1:
  127:       /* select error */
  128:       break;
  129:     case 0:
  130:     default:
  131:       /* timeout or readable/writable sockets */
  132:       curl_multi_perform(multi_handle, &still_running);
  133:       break;
  134:     }
  135:   }
  136: 
  137:   curl_multi_cleanup(multi_handle);
  138: 
  139:   curl_easy_cleanup(http_handle);
  140:   curl_easy_cleanup(http_handle2);
  141: 
  142:   return 0;
  143: }