nng_ctx_recvmsg

NAME

nng_ctx_recvmsg — receive message using socket

SYNOPSIS

#include <nng/nng.h>

int nng_ctx_recvmsg(nng_ctx ctx, nng_msg **msgp, int flags);

DESCRIPTION

The nng_ctx_recvmsg() receives a message on context ctx, storing the received message at the location pointed to by msgp.

The flags may contain the following value:

  • NNG_FLAG_NONBLOCK:
    The function returns immediately, even if no message is available. Without this flag, the function will wait until a message is receivable on the context ctx, or any configured timer expires.

tip

The semantics of what receiving a message means vary from protocol to protocol, so examination of the protocol documentation is encouraged.

RETURN VALUES

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

ERRORS

  • NNG_EAGAIN: The operation would block, but NNG_FLAG_NONBLOCK was specified.
  • NNG_ECLOSED: The context or socket is not open.
  • NNG_EINVAL: An invalid set of flags was specified.
  • NNG_ENOMEM: Insufficient memory is available.
  • NNG_ENOTSUP: The protocol does not support receiving.
  • NNG_ESTATE: The context cannot receive data in this state.
  • NNG_ETIMEDOUT: The operation timed out.

SEE ALSO

nng_msg_free(), nng_ctx_open(), nng_ctx_recv(), nng_ctx_sendmsg()