curl/docs/examples/multi-double.c
Dave Reisner 4c070de4fb examples: use do/while loop for multi examples
It's conceivable that after the first time curl_multi_perform returns,
the outvalue still_running will be 0, but work will have been done. This
is shown by a workload of small, purely file:// based URLs. Ensure that
we always read pending messages off the multi handle by forcing the
while loop to run at least once.
2012-08-27 15:10:13 +02:00

120 lines
3.3 KiB
C

/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2011, 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 http://curl.haxx.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.
*
***************************************************************************/
#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; /* keep number of running handles */
http_handle = curl_easy_init();
http_handle2 = curl_easy_init();
/* set options */
curl_easy_setopt(http_handle, CURLOPT_URL, "http://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);
do {
struct timeval timeout;
int rc; /* select() 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 */
curl_multi_fdset(multi_handle, &fdread, &fdwrite, &fdexcep, &maxfd);
/* In a real-world program you OF COURSE check the return code of the
function calls. On success, the value of maxfd is guaranteed to be
greater or equal than -1. We call select(maxfd + 1, ...), specially in
case of (maxfd == -1), we call select(0, ...), which is basically equal
to sleep. */
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;
}
} while(still_running);
curl_multi_cleanup(multi_handle);
curl_easy_cleanup(http_handle);
curl_easy_cleanup(http_handle2);
return 0;
}