Return to pop3-multi.c CVS log

Up to [ELWIX - Embedded LightWeight unIX -] / embedaddon / curl / docs / examples

curl

    1: /***************************************************************************
    2:  *                                  _   _ ____  _
    3:  *  Project                     ___| | | |  _ \| |
    4:  *                             / __| | | | |_) | |
    5:  *                            | (__| |_| |  _ <| |___
    6:  *                             \___|\___/|_| \_\_____|
    7:  *
    8:  * Copyright (C) 1998 - 2017, 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: 
   23: /* <DESC>
   24:  * POP3 example using the multi interface
   25:  * </DESC>
   26:  */
   27: 
   28: #include <stdio.h>
   29: #include <string.h>
   30: #include <curl/curl.h>
   31: 
   32: /* This is a simple example showing how to retrieve mail using libcurl's POP3
   33:  * capabilities. It builds on the pop3-retr.c example to demonstrate how to use
   34:  * libcurl's multi interface.
   35:  *
   36:  * Note that this example requires libcurl 7.20.0 or above.
   37:  */
   38: 
   39: #define MULTI_PERFORM_HANG_TIMEOUT 60 * 1000
   40: 
   41: static struct timeval tvnow(void)
   42: {
   43:   struct timeval now;
   44: 
   45:   /* time() returns the value of time in seconds since the epoch */
   46:   now.tv_sec = (long)time(NULL);
   47:   now.tv_usec = 0;
   48: 
   49:   return now;
   50: }
   51: 
   52: static long tvdiff(struct timeval newer, struct timeval older)
   53: {
   54:   return (newer.tv_sec - older.tv_sec) * 1000 +
   55:     (newer.tv_usec - older.tv_usec) / 1000;
   56: }
   57: 
   58: int main(void)
   59: {
   60:   CURL *curl;
   61:   CURLM *mcurl;
   62:   int still_running = 1;
   63:   struct timeval mp_start;
   64: 
   65:   curl_global_init(CURL_GLOBAL_DEFAULT);
   66: 
   67:   curl = curl_easy_init();
   68:   if(!curl)
   69:     return 1;
   70: 
   71:   mcurl = curl_multi_init();
   72:   if(!mcurl)
   73:     return 2;
   74: 
   75:   /* Set username and password */
   76:   curl_easy_setopt(curl, CURLOPT_USERNAME, "user");
   77:   curl_easy_setopt(curl, CURLOPT_PASSWORD, "secret");
   78: 
   79:   /* This will retrieve message 1 from the user's mailbox */
   80:   curl_easy_setopt(curl, CURLOPT_URL, "pop3://pop.example.com/1");
   81: 
   82:   /* Tell the multi stack about our easy handle */
   83:   curl_multi_add_handle(mcurl, curl);
   84: 
   85:   /* Record the start time which we can use later */
   86:   mp_start = tvnow();
   87: 
   88:   /* We start some action by calling perform right away */
   89:   curl_multi_perform(mcurl, &still_running);
   90: 
   91:   while(still_running) {
   92:     struct timeval timeout;
   93:     fd_set fdread;
   94:     fd_set fdwrite;
   95:     fd_set fdexcep;
   96:     int maxfd = -1;
   97:     int rc;
   98:     CURLMcode mc; /* curl_multi_fdset() return code */
   99: 
  100:     long curl_timeo = -1;
  101: 
  102:     /* Initialise the file descriptors */
  103:     FD_ZERO(&fdread);
  104:     FD_ZERO(&fdwrite);
  105:     FD_ZERO(&fdexcep);
  106: 
  107:     /* Set a suitable timeout to play around with */
  108:     timeout.tv_sec = 1;
  109:     timeout.tv_usec = 0;
  110: 
  111:     curl_multi_timeout(mcurl, &curl_timeo);
  112:     if(curl_timeo >= 0) {
  113:       timeout.tv_sec = curl_timeo / 1000;
  114:       if(timeout.tv_sec > 1)
  115:         timeout.tv_sec = 1;
  116:       else
  117:         timeout.tv_usec = (curl_timeo % 1000) * 1000;
  118:     }
  119: 
  120:     /* get file descriptors from the transfers */
  121:     mc = curl_multi_fdset(mcurl, &fdread, &fdwrite, &fdexcep, &maxfd);
  122: 
  123:     if(mc != CURLM_OK) {
  124:       fprintf(stderr, "curl_multi_fdset() failed, code %d.\n", mc);
  125:       break;
  126:     }
  127: 
  128:     /* On success the value of maxfd is guaranteed to be >= -1. We call
  129:        select(maxfd + 1, ...); specially in case of (maxfd == -1) there are
  130:        no fds ready yet so we call select(0, ...) --or Sleep() on Windows--
  131:        to sleep 100ms, which is the minimum suggested value in the
  132:        curl_multi_fdset() doc. */
  133: 
  134:     if(maxfd == -1) {
  135: #ifdef _WIN32
  136:       Sleep(100);
  137:       rc = 0;
  138: #else
  139:       /* Portable sleep for platforms other than Windows. */
  140:       struct timeval wait = { 0, 100 * 1000 }; /* 100ms */
  141:       rc = select(0, NULL, NULL, NULL, &wait);
  142: #endif
  143:     }
  144:     else {
  145:       /* Note that on some platforms 'timeout' may be modified by select().
  146:          If you need access to the original value save a copy beforehand. */
  147:       rc = select(maxfd + 1, &fdread, &fdwrite, &fdexcep, &timeout);
  148:     }
  149: 
  150:     if(tvdiff(tvnow(), mp_start) > MULTI_PERFORM_HANG_TIMEOUT) {
  151:       fprintf(stderr,
  152:               "ABORTING: Since it seems that we would have run forever.\n");
  153:       break;
  154:     }
  155: 
  156:     switch(rc) {
  157:     case -1:  /* select error */
  158:       break;
  159:     case 0:   /* timeout */
  160:     default:  /* action */
  161:       curl_multi_perform(mcurl, &still_running);
  162:       break;
  163:     }
  164:   }
  165: 
  166:   /* Always cleanup */
  167:   curl_multi_remove_handle(mcurl, curl);
  168:   curl_multi_cleanup(mcurl);
  169:   curl_easy_cleanup(curl);
  170:   curl_global_cleanup();
  171: 
  172:   return 0;
  173: }