1/***************************************************************************
2 *                                  _   _ ____  _
3 *  Project                     ___| | | |  _ \| |
4 *                             / __| | | | |_) | |
5 *                            | (__| |_| |  _ <| |___
6 *                             \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 1998 - 2016, 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 */
39int main(void)
40{
41  CURL *http_handle;
42  CURL *http_handle2;
43  CURLM *multi_handle;
44
45  int still_running; /* 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, "http://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  do {
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  } while(still_running);
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}
144