= nng_ctx_recvmsg(3)
//
// Copyright 2021 Staysail Systems, Inc. <info@staysail.tech>
//
// This document is supplied under the terms of the MIT License, a
// copy of which should be located in the distribution where this
// file was obtained (LICENSE.txt).  A copy of the license may also be
// found online at https://opensource.org/licenses/MIT.
//

== NAME

nng_ctx_recvmsg - receive message using socket

== SYNOPSIS

[source, c]
----
#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.

NOTE: 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

[horizontal]
`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

[.text-left]
xref:nng_msg_free.3.adoc[nng_msg_free(3)],
xref:nng_ctx_open.3.adoc[nng_ctx_open(3)],
xref:nng_ctx_recv.3.adoc[nng_ctx_recv(3)],
xref:nng_ctx_sendmsg.3.adoc[nng_ctx_sendmsg(3)],
xref:nng_strerror.3.adoc[nng_strerror(3)],
xref:nng_ctx.5.adoc[nng_ctx(5)],
xref:nng.7.adoc[nng(7)]