/*************************************************************************** * _ _ ____ _ * 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> * POP3 example using the multi interface * </DESC> */ #include <stdio.h> #include <string.h> #include <curl/curl.h> /* This is a simple example showing how to retrieve mail using libcurl's POP3 * capabilities. It builds on the pop3-retr.c example to demonstrate how to use * libcurl's multi interface. * * Note that this example requires libcurl 7.20.0 or above. */ #define MULTI_PERFORM_HANG_TIMEOUT 60 * 1000 static struct timeval tvnow(void) { struct timeval now; /* time() returns the value of time in seconds since the epoch */ now.tv_sec = (long)time(NULL); now.tv_usec = 0; return now; } static long tvdiff(struct timeval newer, struct timeval older) { return (newer.tv_sec - older.tv_sec) * 1000 + (newer.tv_usec - older.tv_usec) / 1000; } int main(void) { CURL *curl; CURLM *mcurl; int still_running = 1; struct timeval mp_start; curl_global_init(CURL_GLOBAL_DEFAULT); curl = curl_easy_init(); if(!curl) return 1; mcurl = curl_multi_init(); if(!mcurl) return 2; /* Set username and password */ curl_easy_setopt(curl, CURLOPT_USERNAME, "user"); curl_easy_setopt(curl, CURLOPT_PASSWORD, "secret"); /* This will retrieve message 1 from the user's mailbox */ curl_easy_setopt(curl, CURLOPT_URL, "pop3://pop.example.com/1"); /* Tell the multi stack about our easy handle */ curl_multi_add_handle(mcurl, curl); /* Record the start time which we can use later */ mp_start = tvnow(); /* We start some action by calling perform right away */ curl_multi_perform(mcurl, &still_running); while(still_running) { struct timeval timeout; fd_set fdread; fd_set fdwrite; fd_set fdexcep; int maxfd = -1; int rc; CURLMcode mc; /* curl_multi_fdset() return code */ long curl_timeo = -1; /* Initialise the file descriptors */ 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(mcurl, &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(mcurl, &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); } if(tvdiff(tvnow(), mp_start) > MULTI_PERFORM_HANG_TIMEOUT) { fprintf(stderr, "ABORTING: Since it seems that we would have run forever.\n"); break; } switch(rc) { case -1: /* select error */ break; case 0: /* timeout */ default: /* action */ curl_multi_perform(mcurl, &still_running); break; } } /* Always cleanup */ curl_multi_remove_handle(mcurl, curl); curl_multi_cleanup(mcurl); curl_easy_cleanup(curl); curl_global_cleanup(); return 0; }