#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);nng_pipe_notify(3)
NAME
nng_pipe_notify - register pipe notification callback
SYNOPSIS
DESCRIPTION
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:
NNG_PIPE_EV_ADD_PRE-
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. NNG_PIPE_EV_ADD_POST-
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.
NNG_PIPE_EV_REM_POST-
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 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. |
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. |
RETURN VALUES
This function returns 0 on success, and non-zero otherwise.
ERRORS
NNG_ECLOSED
|
The socket s does not refer to an open socket. |