/*************************************************************************** * _ _ ____ _ * Project ___| | | | _ \| | * / __| | | | |_) | | * | (__| |_| | _ <| |___ * \___|\___/|_| \_\_____| * * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al. * * This software is licensed as described in the file COPYING, which * you should have received as part of this distribution. The terms * are also available at https://curl.se/docs/copyright.html. * * You may opt to use, copy, modify, merge, publish, distribute and/or sell * copies of the Software, and permit persons to whom the Software is * furnished to do so, under the terms of the COPYING file. * * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY * KIND, either express or implied. * ***************************************************************************/ /* <DESC> * multi interface code doing two parallel HTTP transfers * </DESC> */ #include <stdio.h> #include <string.h> /* somewhat unix-specific */ #include <sys/time.h> #include <unistd.h> /* curl stuff */ #include <curl/curl.h> /* * Simply download two HTTP files! */ int main(void) { CURL *http_handle; CURL *http_handle2; CURLM *multi_handle; int still_running = 0; /* keep number of running handles */ http_handle = curl_easy_init(); http_handle2 = curl_easy_init(); /* set options */ curl_easy_setopt(http_handle, CURLOPT_URL, "https://www.example.com/"); /* set options */ curl_easy_setopt(http_handle2, CURLOPT_URL, "http://localhost/"); /* init a multi stack */ multi_handle = curl_multi_init(); /* add the individual transfers */ curl_multi_add_handle(multi_handle, http_handle); curl_multi_add_handle(multi_handle, http_handle2); /* we start some action by calling perform right away */ curl_multi_perform(multi_handle, &still_running); while(still_running) { struct timeval timeout; int rc; /* select() return code */ CURLMcode mc; /* curl_multi_fdset() return code */ fd_set fdread; fd_set fdwrite; fd_set fdexcep; int maxfd = -1; long curl_timeo = -1; FD_ZERO(&fdread); FD_ZERO(&fdwrite); FD_ZERO(&fdexcep); /* set a suitable timeout to play around with */ timeout.tv_sec = 1; timeout.tv_usec = 0; curl_multi_timeout(multi_handle, &curl_timeo); if(curl_timeo >= 0) { timeout.tv_sec = curl_timeo / 1000; if(timeout.tv_sec > 1) timeout.tv_sec = 1; else timeout.tv_usec = (curl_timeo % 1000) * 1000; } /* get file descriptors from the transfers */ mc = curl_multi_fdset(multi_handle, &fdread, &fdwrite, &fdexcep, &maxfd); if(mc != CURLM_OK) { fprintf(stderr, "curl_multi_fdset() failed, code %d.\n", mc); break; } /* On success the value of maxfd is guaranteed to be >= -1. We call select(maxfd + 1, ...); specially in case of (maxfd == -1) there are no fds ready yet so we call select(0, ...) --or Sleep() on Windows-- to sleep 100ms, which is the minimum suggested value in the curl_multi_fdset() doc. */ if(maxfd == -1) { #ifdef _WIN32 Sleep(100); rc = 0; #else /* Portable sleep for platforms other than Windows. */ struct timeval wait = { 0, 100 * 1000 }; /* 100ms */ rc = select(0, NULL, NULL, NULL, &wait); #endif } else { /* Note that on some platforms 'timeout' may be modified by select(). If you need access to the original value save a copy beforehand. */ rc = select(maxfd + 1, &fdread, &fdwrite, &fdexcep, &timeout); } switch(rc) { case -1: /* select error */ break; case 0: default: /* timeout or readable/writable sockets */ curl_multi_perform(multi_handle, &still_running); break; } } curl_multi_cleanup(multi_handle); curl_easy_cleanup(http_handle); curl_easy_cleanup(http_handle2); return 0; }