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curl/docs/examples/multi-app.c
Jay Satiro a607f8a20c examples: Don't call select() to sleep on windows
Windows does not support using select() for sleeping without a dummy
socket. Instead use Windows' Sleep() and sleep for 100ms which is the
minimum suggested value in the curl_multi_fdset() doc.

Prior to this change the multi examples would exit prematurely since
select() would error instead of sleeping when called without an fd.

Reported-by: Johan Lantz
Bug: http://curl.haxx.se/mail/lib-2014-11/0221.html
2014-11-15 21:27:20 +01:00

171 lines
4.8 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.
*
***************************************************************************/
/* This is an example application source code using the multi interface. */
#include <stdio.h>
#include <string.h>
/* somewhat unix-specific */
#include <sys/time.h>
#include <unistd.h>
/* curl stuff */
#include <curl/curl.h>
/*
* Download a HTTP file and upload an FTP file simultaneously.
*/
#define HANDLECOUNT 2 /* Number of simultaneous transfers */
#define HTTP_HANDLE 0 /* Index for the HTTP transfer */
#define FTP_HANDLE 1 /* Index for the FTP transfer */
int main(void)
{
CURL *handles[HANDLECOUNT];
CURLM *multi_handle;
int still_running; /* keep number of running handles */
int i;
CURLMsg *msg; /* for picking up messages with the transfer status */
int msgs_left; /* how many messages are left */
/* Allocate one CURL handle per transfer */
for (i=0; i<HANDLECOUNT; i++)
handles[i] = curl_easy_init();
/* set the options (I left out a few, you'll get the point anyway) */
curl_easy_setopt(handles[HTTP_HANDLE], CURLOPT_URL, "http://example.com");
curl_easy_setopt(handles[FTP_HANDLE], CURLOPT_URL, "ftp://example.com");
curl_easy_setopt(handles[FTP_HANDLE], CURLOPT_UPLOAD, 1L);
/* init a multi stack */
multi_handle = curl_multi_init();
/* add the individual transfers */
for (i=0; i<HANDLECOUNT; i++)
curl_multi_add_handle(multi_handle, handles[i]);
/* 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 */
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) we call
select(0, ...), which is basically equal to sleeping the timeout. On
Windows we can't sleep via select without a dummy socket and instead
we Sleep() for 100ms which is the minimum suggested value in the
curl_multi_fdset() doc. */
#ifdef _WIN32
if(maxfd == -1) {
Sleep(100);
rc = 0;
}
else
#endif
{
rc = select(maxfd+1, &fdread, &fdwrite, &fdexcep, &timeout);
}
switch(rc) {
case -1:
/* select error */
break;
case 0: /* timeout */
default: /* action */
curl_multi_perform(multi_handle, &still_running);
break;
}
} while(still_running);
/* See how the transfers went */
while ((msg = curl_multi_info_read(multi_handle, &msgs_left))) {
if (msg->msg == CURLMSG_DONE) {
int idx, found = 0;
/* Find out which handle this message is about */
for (idx=0; idx<HANDLECOUNT; idx++) {
found = (msg->easy_handle == handles[idx]);
if(found)
break;
}
switch (idx) {
case HTTP_HANDLE:
printf("HTTP transfer completed with status %d\n", msg->data.result);
break;
case FTP_HANDLE:
printf("FTP transfer completed with status %d\n", msg->data.result);
break;
}
}
}
curl_multi_cleanup(multi_handle);
/* Free the CURL handles */
for (i=0; i<HANDLECOUNT; i++)
curl_easy_cleanup(handles[i]);
return 0;
}