nng_ctx_open.3.adoc

nng_ctx_open(3)

NAME

nng_ctx_open - create context

SYNOPSIS

#include <nng/nng.h>

int nng_ctx_open(nng_ctx *ctxp, nng_socket s);

DESCRIPTION

The nng_ctx_open() function creates a separate context to be used with the socket s, and returns it at the location pointed by ctxp.

Note	Not every protocol supports creation of separate contexts.

Contexts allow the independent and concurrent use of stateful operations using the same socket. For example, two different contexts created on a rep socket can each receive requests, and send replies to them, without any regard to or interference with each other.

TIP: Using contexts is an excellent way to write simpler concurrent applications, while retaining the benefits of the protocol-specific advanced processing, avoiding the need to bypass that with raw mode sockets.

Note	Use of contexts with raw mode sockets is nonsensical, and not supported.

RETURN VALUES

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

ERRORS

NNG_ENOMEM	Insufficient memory is available.
NNG_ENOTSUP	The protocol does not support separate contexts, or the socket was opened in raw mode.

SEE ALSO

nng_ctx_close(3), nng_ctx_getopt(3), nng_ctx_recv(3), nng_ctx_send(3), nng_ctx_setopt(3), nng_strerror(3), nng_ctx(5), nng_socket(5), nng_rep(7), nng_req(7), nng(7)