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 */
main(void)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 }
144