curl/docs/libcurl/curl_multi_timeout.3

.\" **************************************************************************
.\" *                                  _   _ ____  _
.\" *  Project                     ___| | | |  _ \| |
.\" *                             / __| | | | |_) | |
.\" *                            | (__| |_| |  _ <| |___
.\" *                             \___|\___/|_| \_\_____|
.\" *
.\" * Copyright (C) 1998 - 2016, 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.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.
.\" *
.\" **************************************************************************
.TH curl_multi_timeout 3 "2 Jan 2006" "libcurl 7.16.0" "libcurl Manual"
.SH NAME
curl_multi_timeout \- how long to wait for action before proceeding
.SH SYNOPSIS
#include <curl/curl.h>

CURLMcode curl_multi_timeout(CURLM *multi_handle, long *timeout);
.SH DESCRIPTION

An application using the libcurl multi interface should call
\fIcurl_multi_timeout(3)\fP to figure out how long it should wait for socket
actions \- at most \- before proceeding.

Proceeding means either doing the socket-style timeout action: call the
\fIcurl_multi_socket_action(3)\fP function with the \fBsockfd\fP argument set
to CURL_SOCKET_TIMEOUT, or call \fIcurl_multi_perform(3)\fP if you're using
the simpler and older multi interface approach.

The timeout value returned in the long \fBtimeout\fP points to, is in number
of milliseconds at this very moment. If 0, it means you should proceed
immediately without waiting for anything. If it returns -1, there's no timeout
at all set.

An application that uses the multi_socket API SHOULD NOT use this function, but
SHOULD instead use \fIcurl_multi_setopt(3)\fP and its
\fPCURLMOPT_TIMERFUNCTION\fP option for proper and desired behavior.

Note: if libcurl returns a -1 timeout here, it just means that libcurl
currently has no stored timeout value. You must not wait too long (more than a
few seconds perhaps) before you call curl_multi_perform() again.
.SH EXAMPLE
.nf
struct timeval timeout;
long timeo;

curl_multi_timeout(multi_handle, &timeo);
if(timeo < 0)
  /* no set timeout, use a default */
  timeo = 980;

timeout.tv_sec = timeo / 1000;
timeout.tv_usec = (timeo % 1000) * 1000;

/* wait for activities no longer than the set timeout */
select(maxfd+1, &fdread, &fdwrite, &fdexcep, &timeout);
.fi
.SH "RETURN VALUE"
The standard CURLMcode for multi interface error codes.
.SH "TYPICAL USAGE"
Call \fIcurl_multi_timeout(3)\fP, then wait for action on the sockets. You
figure out which sockets to wait for by calling \fIcurl_multi_fdset(3)\fP or
by a previous call to \fIcurl_multi_socket(3)\fP.
.SH AVAILABILITY
This function was added in libcurl 7.15.4.
.SH "SEE ALSO"
.BR curl_multi_fdset "(3), " curl_multi_info_read "(3), "
.BR curl_multi_socket "(3), " curl_multi_setopt "(3) "