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Annotation of embedaddon/curl/docs/examples/multi-double.c, revision 1.1.1.1

1.1       misho       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: }