adjusted to the new concept of the callback

.\" $Id$

.\"

.TH curl_multi_setopt 3 "8 Jan 2006" "libcurl 7.16.0" "libcurl Manual"

.SH NAME

curl_multi_setopt \- set options for a curl multi handle

.SH SYNOPSIS

#include <curl/curl.h>

CURLMcode curl_multi_setopt(CURLM * multi_handle, CURLMoption option, param);

.SH DESCRIPTION

curl_multi_setopt() is used to tell a libcurl multi handle how to behave. By

using the appropriate options to \fIcurl_multi_setopt\fP, you can change

libcurl's behaviour when using that multi handle.  All options are set with

the \fIoption\fP followed by the parameter \fIparam\fP. That parameter can be

a \fBlong\fP, a \fBfunction pointer\fP, an \fBobject pointer\fP or a

\fBcurl_off_t\fP type, depending on what the specific option expects. Read

this manual carefully as bad input values may cause libcurl to behave badly!

You can only set one option in each function call.

.SH OPTIONS

.IP CURLMOPT_SOCKETFUNCTION

Pass a pointer to a function matching the curl_socket_callback prototype. The

\fIcurl_multi_socket(3)\fP functions inform the application about updates in

the socket (file descriptor) status by doing none, one or multiple calls to

the curl_socket_callback given in the \fBparam\fP argument. They update the

status with changes since the previous time a \fIcurl_multi_socket(3)\fP

function was called. If the given callback pointer is NULL, no callback will

be called. Set the callback's fourth argument with \fICURLMOPT_SOCKETDATA\fP.

See \fIcurl_multi_socket(3)\fP for more callback details.

.IP CURLMOPT_SOCKETDATA

Pass a pointer to whatever you want passed to the curl_socket_callback's forth

argument, the userp pointer. This is not used by libcurl but only passed-thru

as-is. Set the callback pointer with \fICURLMOPT_SOCKETFUNCTION\fP.

.SH RETURNS

The standard CURLMcode for multi interface error codes. Note that it returns a

CURLM_UNKNOWN_OPTION if you try setting an option that this version of libcurl

doesn't know of.

.SH AVAILABILITY

This function was added in libcurl 7.16.0

.SH "SEE ALSO"

.BR curl_multi_cleanup "(3), " curl_multi_init "(3), "

.BR curl_multi_socket "(3), " curl_multi_info_read "(3)"

.SH SYNOPSIS

#include <curl/curl.h>

CURLMcode curl_multi_socket(CURLM * multi_handle,

                            curl_socket_t sockfd,

                            curl_socket_callback callback,

                            void *userp);

CURLMcode curl_multi_socket_all(CURLM *multi_handle,

                                curl_socket_callback callback,

                                void *userp);

CURLMcode curl_multi_socket(CURLM * multi_handle, curl_socket_t sockfd);

CURLMcode curl_multi_socket_all(CURLM *multi_handle);

.SH DESCRIPTION

Alternative versions of \fIcurl_multi_perform()\fP that allows the application

to pass in one of the file descriptors/sockets that have been detected to have

\&"action" on them and let libcurl perform. This allows libcurl to not have to

scan through all possible file descriptors to check for action. When the

application has detected on a socket handled by libcurl, call

application has detected action on a socket handled by libcurl, it should call

\fIcurl_multi_perform()\fP with the \fBsockfd\fP argument set to the socket

with the action.

These functions inform the application about updates in the socket (file

descriptor) status by doing none, one or multiple calls to the

curl_socket_callback given in the \fBcallback\fP argument. They update the

status with changes since the previous time this function was used. If

\fBcallback\fP is NULL, no callback will be called. A status change may also

be a new timeout only, having the same IN/OUT status as before.

curl_socket_callback given with the CURLMOPT_SOCKETFUNCTION option to

\fIcurl_multi_setopt(3)\fP. They update the status with changes since the

previous time this function was called.

If you want to force libcurl to (re-)check all its internal sockets and

transfers instead of just a single one, you call

action: call the \fBcurl_multi_socket(3)\fP function with the \fBsockfd\fP

argument set to CURL_SOCKET_TIMEOUT.

\fBcurl_multi_perform(3)\fP is the exact equivalent of calling

\fBcurl_multi_socket_all\fP(handle, NULL, NULL);

The socket \fBcallback\fP function uses a prototype like this

.nf

CURLMcode type, general libcurl multi interface error code.

If you receive \fICURLM_CALL_MULTI_PERFORM\fP, this basically means that you

should call \fIcurl_multi_perform\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".

should call \fIcurl_multi_perform\fP again, before you wait for more actions

on libcurl's sockets. 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".

NOTE that this only returns errors etc regarding the whole multi stack. There

might still have occurred problems on individual transfers even when this

function returns OK.

.SH "TYPICAL USAGE"

Call curl_multi_socket_all() first. Setup a "collection" of sockets to

supervise, then when action happens call curl_multi_socket() for the easy

handle that got the action.

1. Create a multi handle

2. Set the socket callback with CURLMOPT_SOCKETFUNCTION

3. Add easy handles

4. Call curl_multi_socket_all() first once

5. Setup a "collection" of sockets to supervise when your socket

callback is called.

6. Use curl_multi_timeout() to figure out how long to wait for action

7. Wait for action on any of libcurl's sockets

8, When action happens, call curl_multi_socket() for the socket(s) that got

action.

9. Go back to step 6.

.SH AVAILABILITY

This function was added in libcurl 7.16.0

.SH "SEE ALSO"