When the multi:SocketAction() 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.
The callback receives three arguments: The first argument is an easy handle, the second argument is a socket descriptor, and the third argument informs the callback on the status of the given socket. It can hold one of these values:
If you pass the optional
userdata argument, the value you pass in
be passed to your callback function as a fourth parameter. The
can be of any type.