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

1.1       misho       1: /***************************************************************************
                      2:  *                                  _   _ ____  _
                      3:  *  Project                     ___| | | |  _ \| |
                      4:  *                             / __| | | | |_) | |
                      5:  *                            | (__| |_| |  _ <| |___
                      6:  *                             \___|\___/|_| \_\_____|
                      7:  *
                      8:  * Copyright (C) 1998 - 2019, 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:  * A basic application source code using the multi interface doing two
                     24:  * transfers in parallel.
                     25:  * </DESC>
                     26:  */
                     27: 
                     28: #include <stdio.h>
                     29: #include <string.h>
                     30: 
                     31: /* somewhat unix-specific */
                     32: #include <sys/time.h>
                     33: #include <unistd.h>
                     34: 
                     35: /* curl stuff */
                     36: #include <curl/curl.h>
                     37: 
                     38: /*
                     39:  * Download a HTTP file and upload an FTP file simultaneously.
                     40:  */
                     41: 
                     42: #define HANDLECOUNT 2   /* Number of simultaneous transfers */
                     43: #define HTTP_HANDLE 0   /* Index for the HTTP transfer */
                     44: #define FTP_HANDLE 1    /* Index for the FTP transfer */
                     45: 
                     46: int main(void)
                     47: {
                     48:   CURL *handles[HANDLECOUNT];
                     49:   CURLM *multi_handle;
                     50: 
                     51:   int still_running = 0; /* keep number of running handles */
                     52:   int i;
                     53: 
                     54:   CURLMsg *msg; /* for picking up messages with the transfer status */
                     55:   int msgs_left; /* how many messages are left */
                     56: 
                     57:   /* Allocate one CURL handle per transfer */
                     58:   for(i = 0; i<HANDLECOUNT; i++)
                     59:     handles[i] = curl_easy_init();
                     60: 
                     61:   /* set the options (I left out a few, you'll get the point anyway) */
                     62:   curl_easy_setopt(handles[HTTP_HANDLE], CURLOPT_URL, "https://example.com");
                     63: 
                     64:   curl_easy_setopt(handles[FTP_HANDLE], CURLOPT_URL, "ftp://example.com");
                     65:   curl_easy_setopt(handles[FTP_HANDLE], CURLOPT_UPLOAD, 1L);
                     66: 
                     67:   /* init a multi stack */
                     68:   multi_handle = curl_multi_init();
                     69: 
                     70:   /* add the individual transfers */
                     71:   for(i = 0; i<HANDLECOUNT; i++)
                     72:     curl_multi_add_handle(multi_handle, handles[i]);
                     73: 
                     74:   /* we start some action by calling perform right away */
                     75:   curl_multi_perform(multi_handle, &still_running);
                     76: 
                     77:   while(still_running) {
                     78:     struct timeval timeout;
                     79:     int rc; /* select() return code */
                     80:     CURLMcode mc; /* curl_multi_fdset() return code */
                     81: 
                     82:     fd_set fdread;
                     83:     fd_set fdwrite;
                     84:     fd_set fdexcep;
                     85:     int maxfd = -1;
                     86: 
                     87:     long curl_timeo = -1;
                     88: 
                     89:     FD_ZERO(&fdread);
                     90:     FD_ZERO(&fdwrite);
                     91:     FD_ZERO(&fdexcep);
                     92: 
                     93:     /* set a suitable timeout to play around with */
                     94:     timeout.tv_sec = 1;
                     95:     timeout.tv_usec = 0;
                     96: 
                     97:     curl_multi_timeout(multi_handle, &curl_timeo);
                     98:     if(curl_timeo >= 0) {
                     99:       timeout.tv_sec = curl_timeo / 1000;
                    100:       if(timeout.tv_sec > 1)
                    101:         timeout.tv_sec = 1;
                    102:       else
                    103:         timeout.tv_usec = (curl_timeo % 1000) * 1000;
                    104:     }
                    105: 
                    106:     /* get file descriptors from the transfers */
                    107:     mc = curl_multi_fdset(multi_handle, &fdread, &fdwrite, &fdexcep, &maxfd);
                    108: 
                    109:     if(mc != CURLM_OK) {
                    110:       fprintf(stderr, "curl_multi_fdset() failed, code %d.\n", mc);
                    111:       break;
                    112:     }
                    113: 
                    114:     /* On success the value of maxfd is guaranteed to be >= -1. We call
                    115:        select(maxfd + 1, ...); specially in case of (maxfd == -1) there are
                    116:        no fds ready yet so we call select(0, ...) --or Sleep() on Windows--
                    117:        to sleep 100ms, which is the minimum suggested value in the
                    118:        curl_multi_fdset() doc. */
                    119: 
                    120:     if(maxfd == -1) {
                    121: #ifdef _WIN32
                    122:       Sleep(100);
                    123:       rc = 0;
                    124: #else
                    125:       /* Portable sleep for platforms other than Windows. */
                    126:       struct timeval wait = { 0, 100 * 1000 }; /* 100ms */
                    127:       rc = select(0, NULL, NULL, NULL, &wait);
                    128: #endif
                    129:     }
                    130:     else {
                    131:       /* Note that on some platforms 'timeout' may be modified by select().
                    132:          If you need access to the original value save a copy beforehand. */
                    133:       rc = select(maxfd + 1, &fdread, &fdwrite, &fdexcep, &timeout);
                    134:     }
                    135: 
                    136:     switch(rc) {
                    137:     case -1:
                    138:       /* select error */
                    139:       break;
                    140:     case 0: /* timeout */
                    141:     default: /* action */
                    142:       curl_multi_perform(multi_handle, &still_running);
                    143:       break;
                    144:     }
                    145:   }
                    146: 
                    147:   /* See how the transfers went */
                    148:   while((msg = curl_multi_info_read(multi_handle, &msgs_left))) {
                    149:     if(msg->msg == CURLMSG_DONE) {
                    150:       int idx;
                    151: 
                    152:       /* Find out which handle this message is about */
                    153:       for(idx = 0; idx<HANDLECOUNT; idx++) {
                    154:         int found = (msg->easy_handle == handles[idx]);
                    155:         if(found)
                    156:           break;
                    157:       }
                    158: 
                    159:       switch(idx) {
                    160:       case HTTP_HANDLE:
                    161:         printf("HTTP transfer completed with status %d\n", msg->data.result);
                    162:         break;
                    163:       case FTP_HANDLE:
                    164:         printf("FTP transfer completed with status %d\n", msg->data.result);
                    165:         break;
                    166:       }
                    167:     }
                    168:   }
                    169: 
                    170:   curl_multi_cleanup(multi_handle);
                    171: 
                    172:   /* Free the CURL handles */
                    173:   for(i = 0; i<HANDLECOUNT; i++)
                    174:     curl_easy_cleanup(handles[i]);
                    175: 
                    176:   return 0;
                    177: }

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