This documentation is for version v1.3.0 of NNG, but the latest released version is v1.8.0. see the documentation for v1.8.0 for the most up-to-date information.


#include <nng/nng.h>

typedef enum {
} 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);


The nng_pipe_notify() function registers the callback function cb to be called whenever a pipe the pipe event specified by ev occurs on the socket s. The callback cb will be passed arg as its final argument.

A different callback may be supplied for each event. Each event may have at most one callback registered. Registering a callback implicitly unregisters any previously registered.

The following pipe events are supported:


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.

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


This function returns 0 on success, and non-zero otherwise.



The socket s does not refer to an open socket.