mirror of
https://github.com/moparisthebest/curl
synced 2024-11-07 01:55:05 -05:00
97 lines
3.5 KiB
Groff
97 lines
3.5 KiB
Groff
.\" $Id$
|
|
.\"
|
|
.TH curl_multi_socket 3 "21 Dec 2005" "libcurl 7.16.0" "libcurl Manual"
|
|
.SH NAME
|
|
curl_multi_socket \- reads/writes available data
|
|
.SH SYNOPSIS
|
|
#include <curl/curl.h>
|
|
|
|
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 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 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
|
|
\fBcurl_multi_socket_all(3)\fP instead.
|
|
|
|
An application should call \fBcurl_multi_timeout(3)\fP to figure out how long
|
|
it should wait for socket actions \- at most \- before doing the timeout
|
|
action: call the \fBcurl_multi_socket(3)\fP function with the \fBsockfd\fP
|
|
argument set to CURL_SOCKET_TIMEOUT.
|
|
|
|
The socket \fBcallback\fP function uses a prototype like this
|
|
.nf
|
|
|
|
int curl_socket_callback(CURL *easy, /* easy handle */
|
|
curl_socket_t s, /* socket */
|
|
int action, /* see values below */
|
|
void *userp); /* "private" pointer */
|
|
|
|
.fi
|
|
The callback MUST return 0.
|
|
|
|
The \fIaction\fP (third) argument to the callback has one of five values:
|
|
.RS
|
|
.IP "CURL_POLL_NONE (0)"
|
|
register, not interested in readiness (yet)
|
|
.IP "CURL_POLL_IN (1)"
|
|
register, interested in read readiness
|
|
.IP "CURL_POLL_OUT (2)"
|
|
register, interested in write readiness
|
|
.IP "CURL_POLL_INOUT (3)"
|
|
register, interested in both read and write readiness
|
|
.IP "CURL_POLL_REMOVE (4)"
|
|
deregister
|
|
.RE
|
|
.SH "RETURN VALUE"
|
|
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 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"
|
|
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"
|
|
.BR curl_multi_cleanup "(3), " curl_multi_init "(3), "
|
|
.BR curl_multi_fdset "(3), " curl_multi_info_read "(3)"
|