#include <nng/nng.h>
typedef enum {


        NNG_PIPE_EV_ADD_PRE,


        NNG_PIPE_EV_ADD_POST,


        NNG_PIPE_EV_REM_POST,
} nng_pipe_ev;
typedef void (*nng_pipe_cb)(nng_pipe, nng_pipe_ev, void *);
int nng_pipe_notify(nng_socket s, nng_pipe_ev ev, nng_pipe_cb cb, void *arg);

This event occurs after a connection and negotiation has completed, but before the pipe is added to the socket. If the pipe is closed (using nng_pipe_close()) at this point, the socket will never see the pipe, and no further events will occur for the given pipe.

This event occurs after the pipe is fully added to the socket. Prior to this time, it is not possible to communicate over the pipe with the socket.

This event occurs after the pipe has been removed from the socket. The underlying transport may be closed at this point, and it is not possible communicate using this pipe.

Warning

The callback cb function must not attempt to perform any
accesses to the socket, as it is called with a lock on the socket held! Doing so would thus result in a deadlock.

Tip

The callback cb may close a pipe for any reason by simply closing
it using nng_pipe_close(). This might be done before the pipe is added to the socket (during NNG_PIPE_EV_ADD_PRE), for example, if the remote peer is not authorized.

Tip

It is possible to register the same cb and arg for different events
by calling this function separately for different values of ev.

Note

This function ignores invalid values for ev.

The socket s does not refer to an open socket.