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.TH CURLMOPT_SOCKETFUNCTION 3 "3 Nov 2014" "libcurl 7.39.0" "curl_multi_setopt options"
.SH NAME
CURLMOPT_SOCKETFUNCTION \- callback informed about what to wait for
.SH SYNOPSIS
.nf
#include <curl/curl.h>

int socket_callback(CURL *easy,      /* easy handle */
                    curl_socket_t s, /* socket */
                    int what,        /* see above */
                    void *userp,     /* private callback pointer */
                    void *socketp);  /* private socket pointer */

CURLMcode curl_multi_setopt(CURLM *handle, CURLMOPT_SOCKETFUNCTION, socket_callback);
.SH DESCRIPTION
Pass a pointer to your callback function, which should match the prototype
shown above.

When the \fIcurl_multi_socket_action(3)\fP function runs, it informs the
application about updates in the socket (file descriptor) status by doing
none, one, or multiple calls to the \fBsocket_callback\fP. The callback gets
status updates with changes since the previous time the callback was called.
If the given callback pointer is NULL, no callback will be called. Set the
callback's \fBuserp\fP argument with \fICURLMOPT_SOCKETDATA(3)\fP.  See
\fIcurl_multi_socket_action(3)\fP for more details on how the callback is used
and should work.
.SH DEFAULT
NULL (no callback)
.SH PROTOCOLS
All
.SH EXAMPLE
TODO
.SH AVAILABILITY
Added in 7.15.4
.SH RETURN VALUE
Returns CURLM_OK.
.SH "SEE ALSO"
.BR CURLMOPT_SOCKETDATA "(3), " curl_multi_socket_action "(3), "
.BR CURLMOPT_TIMERFUNCTION "(3) "