mirror of
https://github.com/moparisthebest/curl
synced 2024-11-05 09:05:04 -05:00
80 lines
4.0 KiB
Groff
80 lines
4.0 KiB
Groff
.\" **************************************************************************
|
|
.\" * _ _ ____ _
|
|
.\" * Project ___| | | | _ \| |
|
|
.\" * / __| | | | |_) | |
|
|
.\" * | (__| |_| | _ <| |___
|
|
.\" * \___|\___/|_| \_\_____|
|
|
.\" *
|
|
.\" * Copyright (C) 1998 - 2014, 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.
|
|
.\" *
|
|
.\" **************************************************************************
|
|
.TH curl_multi_perform 3 "1 March 2002" "libcurl 7.9.5" "libcurl Manual"
|
|
.SH NAME
|
|
curl_multi_perform - reads/writes available data from each easy handle
|
|
.SH SYNOPSIS
|
|
#include <curl/curl.h>
|
|
|
|
CURLMcode curl_multi_perform(CURLM *multi_handle, int *running_handles);
|
|
.ad
|
|
.SH DESCRIPTION
|
|
This function handles transfers on all the added handles that need attention
|
|
in an non-blocking fashion.
|
|
|
|
When an application has found out there's data available for the multi_handle
|
|
or a timeout has elapsed, the application should call this function to
|
|
read/write whatever there is to read or write right now etc.
|
|
\fIcurl_multi_perform(3)\fP returns as soon as the reads/writes are done. This
|
|
function does not require that there actually is any data available for
|
|
reading or that data can be written, it can be called just in case. It will
|
|
write the number of handles that still transfer data in the second argument's
|
|
integer-pointer.
|
|
|
|
If the amount of \fIrunning_handles\fP is changed from the previous call (or
|
|
is less than the amount of easy handles you've added to the multi handle), you
|
|
know that there is one or more transfers less "running". You can then call
|
|
\fIcurl_multi_info_read(3)\fP to get information about each individual
|
|
completed transfer, and that returned info includes CURLcode and more. If an
|
|
added handle fails very quickly, it may never be counted as a running_handle.
|
|
|
|
When \fIrunning_handles\fP is set to zero (0) on the return of this function,
|
|
there is no longer any transfers in progress.
|
|
.SH "RETURN VALUE"
|
|
CURLMcode type, general libcurl multi interface error code.
|
|
|
|
Before version 7.20.0: If you receive \fICURLM_CALL_MULTI_PERFORM\fP, this
|
|
basically means that you should call \fIcurl_multi_perform(3)\fP again, before
|
|
you select() on more actions. You don't have to do it immediately, but the
|
|
return code means that libcurl may have more data available to return or that
|
|
there may be more data to send off before it is "satisfied". Do note that
|
|
\fIcurl_multi_perform(3)\fP will return \fICURLM_CALL_MULTI_PERFORM\fP only
|
|
when it wants to be called again \fBimmediately\fP. When things are fine and
|
|
there is nothing immediate it wants done, it'll return \fICURLM_OK\fP and you
|
|
need to wait for \&"action" and then call this function again.
|
|
|
|
This function only returns errors etc regarding the whole multi stack.
|
|
Problems still might have occurred on individual transfers even when this
|
|
function returns \fICURLM_OK\fP. Use \fIcurl_multi_info_read(3)\fP to figure
|
|
out how individual transfers did.
|
|
.SH "TYPICAL USAGE"
|
|
Most applications will use \fIcurl_multi_fdset(3)\fP to get the multi_handle's
|
|
file descriptors, and \fIcurl_multi_timeout(3)\fP to get a suitable timeout
|
|
period, then it'll wait for action on the file descriptors using
|
|
\fBselect(3)\fP. As soon as one or more file descriptor is ready,
|
|
\fIcurl_multi_perform(3)\fP gets called.
|
|
.SH "SEE ALSO"
|
|
.BR curl_multi_cleanup "(3), " curl_multi_init "(3), "
|
|
.BR curl_multi_wait "(3), "
|
|
.BR curl_multi_fdset "(3), " curl_multi_info_read "(3), "
|
|
.BR libcurl-errors "(3)"
|