mirror of
https://github.com/moparisthebest/curl
synced 2024-11-17 23:15:08 -05:00
97 lines
4.7 KiB
Groff
97 lines
4.7 KiB
Groff
.\" **************************************************************************
|
|
.\" * _ _ ____ _
|
|
.\" * 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.
|
|
.\" *
|
|
.\" **************************************************************************
|
|
.TH curl_multi_socket_action 3 "9 Jul 2006" "libcurl 7.16.0" "libcurl Manual"
|
|
.SH NAME
|
|
curl_multi_socket_action \- reads/writes available data given an action
|
|
.SH SYNOPSIS
|
|
.nf
|
|
#include <curl/curl.h>
|
|
|
|
CURLMcode curl_multi_socket_action(CURLM * multi_handle,
|
|
curl_socket_t sockfd,
|
|
int ev_bitmask,
|
|
int *running_handles);
|
|
.fi
|
|
.SH DESCRIPTION
|
|
When the application has detected action on a socket handled by libcurl, it
|
|
should call \fIcurl_multi_socket_action(3)\fP with the \fBsockfd\fP argument
|
|
set to the socket with the action. When the events on a socket are known, they
|
|
can be passed as an events bitmask \fBev_bitmask\fP by first setting
|
|
\fBev_bitmask\fP to 0, and then adding using bitwise OR (|) any combination of
|
|
events to be chosen from CURL_CSELECT_IN, CURL_CSELECT_OUT or
|
|
CURL_CSELECT_ERR. When the events on a socket are unknown, pass 0 instead, and
|
|
libcurl will test the descriptor internally. It is also permissible to pass
|
|
CURL_SOCKET_TIMEOUT to the \fBsockfd\fP parameter in order to initiate the
|
|
whole process or when a timeout occurs.
|
|
|
|
At return, \fBrunning_handles\fP points to the number of running easy handles
|
|
within the multi handle. When this number reaches zero, all transfers are
|
|
complete/done. When you call \fIcurl_multi_socket_action(3)\fP on a specific
|
|
socket and the counter decreases by one, it DOES NOT necessarily mean that
|
|
this exact socket/transfer is the one that completed. Use
|
|
\fIcurl_multi_info_read(3)\fP to figure out which easy handle that completed.
|
|
|
|
The \fIcurl_multi_socket_action(3)\fP function informs the application about
|
|
updates in the socket (file descriptor) status by doing none, one, or multiple
|
|
calls to the socket callback function set with the
|
|
\fICURLMOPT_SOCKETFUNCTION(3)\fP option to \fIcurl_multi_setopt(3)\fP. They
|
|
update the status with changes since the previous time the callback was
|
|
called.
|
|
|
|
Get the timeout time by setting the \fICURLMOPT_TIMERFUNCTION(3)\fP option
|
|
with \fIcurl_multi_setopt(3)\fP. Your application will then get called with
|
|
information on how long to wait for socket actions at most before doing the
|
|
timeout action: call the \fIcurl_multi_socket_action(3)\fP function with the
|
|
\fBsockfd\fP argument set to CURL_SOCKET_TIMEOUT. You can also use the
|
|
\fIcurl_multi_timeout(3)\fP function to poll the value at any given time, but
|
|
for an event-based system using the callback is far better than relying on
|
|
polling the timeout value.
|
|
.SH "TYPICAL USAGE"
|
|
1. Create a multi handle
|
|
|
|
2. Set the socket callback with \fICURLMOPT_SOCKETFUNCTION(3)\fP
|
|
|
|
3. Set the timeout callback with \fICURLMOPT_TIMERFUNCTION(3)\fP, to get to
|
|
know what timeout value to use when waiting for socket activities.
|
|
|
|
4. Add easy handles with curl_multi_add_handle()
|
|
|
|
5. Provide some means to manage the sockets libcurl is using, so you can check
|
|
them for activity. This can be done through your application code, or by way
|
|
of an external library such as libevent or glib.
|
|
|
|
6. Call curl_multi_socket_action(..., CURL_SOCKET_TIMEOUT, 0, ...)
|
|
to kickstart everything. To get one or more callbacks called.
|
|
|
|
7. Wait for activity on any of libcurl's sockets, use the timeout value your
|
|
callback has been told.
|
|
|
|
8, When activity is detected, call curl_multi_socket_action() for the
|
|
socket(s) that got action. If no activity is detected and the timeout expires,
|
|
call \fIcurl_multi_socket_action(3)\fP with \fICURL_SOCKET_TIMEOUT\fP.
|
|
.SH AVAILABILITY
|
|
This function was added in libcurl 7.15.4, and is deemed stable since 7.16.0.
|
|
.SH "SEE ALSO"
|
|
.BR curl_multi_cleanup "(3), " curl_multi_init "(3), "
|
|
.BR curl_multi_fdset "(3), " curl_multi_info_read "(3), "
|
|
.BR "the hiperfifo.c example"
|