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