1 /*************************************************************************** 2 * _ _ ____ _ 3 * Project ___| | | | _ \| | 4 * / __| | | | |_) | | 5 * | (__| |_| | _ <| |___ 6 * \___|\___/|_| \_\_____| 7 * 8 * Copyright (C) 1998 - 2017, Daniel Stenberg, <daniel (at) 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 */ 39 int 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
