Provided by: libcurl4-doc_7.47.0-1ubuntu2.19_all 

NAME
CURLMOPT_SOCKETFUNCTION - callback informed about what to wait for
SYNOPSIS
#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);
DESCRIPTION
Pass a pointer to your callback function, which should match the prototype shown above.
When the curl_multi_socket_action(3) function runs, it informs the application about updates in the
socket (file descriptor) status by doing none, one, or multiple calls to the socket_callback. 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 userp argument with
CURLMOPT_SOCKETDATA(3). See curl_multi_socket_action(3) for more details on how the callback is used and
should work.
DEFAULT
NULL (no callback)
PROTOCOLS
All
EXAMPLE
TODO
AVAILABILITY
Added in 7.15.4
RETURN VALUE
Returns CURLM_OK.
SEE ALSO
CURLMOPT_SOCKETDATA(3), curl_multi_socket_action(3), CURLMOPT_TIMERFUNCTION(3)
libcurl 7.39.0 3 Nov 2014 CURLMOPT_SOCKETFUNCTION(3)