1/***************************************************************************
2 *                                  _   _ ____  _
3 *  Project                     ___| | | |  _ \| |
4 *                             / __| | | | |_) | |
5 *                            | (__| |_| |  _ <| |___
6 *                             \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 1998 - 2011, 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 http://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/* This is a very simple example using the multi interface. */
23
24#include <stdio.h>
25#include <string.h>
26
27/* somewhat unix-specific */
28#include <sys/time.h>
29#include <unistd.h>
30
31/* curl stuff */
32#include <curl/curl.h>
33
34/*
35 * Simply download a HTTP file.
36 */
37int main(void)
38{
39  CURL *http_handle;
40  CURLM *multi_handle;
41
42  int still_running; /* keep number of running handles */
43
44  http_handle = curl_easy_init();
45
46  /* set the options (I left out a few, you'll get the point anyway) */
47  curl_easy_setopt(http_handle, CURLOPT_URL, "http://www.example.com/");
48
49  /* init a multi stack */
50  multi_handle = curl_multi_init();
51
52  /* add the individual transfers */
53  curl_multi_add_handle(multi_handle, http_handle);
54
55  /* we start some action by calling perform right away */
56  curl_multi_perform(multi_handle, &still_running);
57
58  while(still_running) {
59    struct timeval timeout;
60    int rc; /* select() return code */
61
62    fd_set fdread;
63    fd_set fdwrite;
64    fd_set fdexcep;
65    int maxfd = -1;
66
67    long curl_timeo = -1;
68
69    FD_ZERO(&fdread);
70    FD_ZERO(&fdwrite);
71    FD_ZERO(&fdexcep);
72
73    /* set a suitable timeout to play around with */
74    timeout.tv_sec = 1;
75    timeout.tv_usec = 0;
76
77    curl_multi_timeout(multi_handle, &curl_timeo);
78    if(curl_timeo >= 0) {
79      timeout.tv_sec = curl_timeo / 1000;
80      if(timeout.tv_sec > 1)
81        timeout.tv_sec = 1;
82      else
83        timeout.tv_usec = (curl_timeo % 1000) * 1000;
84    }
85
86    /* get file descriptors from the transfers */
87    curl_multi_fdset(multi_handle, &fdread, &fdwrite, &fdexcep, &maxfd);
88
89    /* In a real-world program you OF COURSE check the return code of the
90       function calls.  On success, the value of maxfd is guaranteed to be
91       greater or equal than -1.  We call select(maxfd + 1, ...), specially in
92       case of (maxfd == -1), we call select(0, ...), which is basically equal
93       to sleep. */
94
95    rc = select(maxfd+1, &fdread, &fdwrite, &fdexcep, &timeout);
96
97    switch(rc) {
98    case -1:
99      /* select error */
100      still_running = 0;
101      printf("select() returns error, this is badness\n");
102      break;
103    case 0:
104    default:
105      /* timeout or readable/writable sockets */
106      curl_multi_perform(multi_handle, &still_running);
107      break;
108    }
109  }
110
111  curl_multi_cleanup(multi_handle);
112
113  curl_easy_cleanup(http_handle);
114
115  return 0;
116}
117