= nng_dialer_start(3)
//
// Copyright 2018 Staysail Systems, Inc. <info@staysail.tech>
// Copyright 2018 Capitar IT Group BV <info@capitar.com>
//
// 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_dialer_start - start dialer

== SYNOPSIS

[source, c]
----
#include <nng/nng.h>

int nng_dialer_start(nng_dialer d, int flags);
----

== DESCRIPTION

The `nng_dialer_start()` function starts the dialer _d_.

This causes the dialer to start connecting to the address with which it was
created.

When a connection is established, it results in a pipe being created,
which will be attached to the dialer's socket.

Normally, the first attempt to connect to the dialer's address is done
synchronously, including any necessary name resolution.
As a result, a failure, such as if the connection is refused, will be returned
immediately, and no further action will be taken.

However, if the special value `NNG_FLAG_NONBLOCK` is
supplied in _flags_, then the connection attempt is made asynchronously.

Furthermore, if the connection was closed for a synchronously dialed
connection, the dialer will still attempt to redial asynchronously.

TIP: While `NNG_FLAG_NONBLOCK` can help an application be more resilient,
it also generally makes diagnosing failures somewhat more difficult.

Once a dialer has started, it is generally not possible to change
its configuration.

== RETURN VALUES

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

== ERRORS

[horizontal]
`NNG_EADDRINVAL`:: An invalid _url_ was specified.
`NNG_ECLOSED`:: The socket _s_ is not open.
`NNG_ECONNREFUSED`:: The remote peer refused the connection.
`NNG_ECONNRESET`:: The remote peer reset the connection.
`NNG_EINVAL`:: An invalid set of _flags_ was specified.
`NNG_ENOMEM`:: Insufficient memory is available.
`NNG_EPEERAUTH`:: Authentication or authorization failure.
`NNG_EPROTO`:: A protocol error occurred.
`NNG_ESTATE`:: The dialer _d_ is already started.
`NNG_EUNREACHABLE`:: The remote address is not reachable.

== SEE ALSO

[.text-left]
xref:nng_dial.3.adoc[nng_dial(3)],
xref:nng_dialer_create.3.adoc[nng_dialer_create(3)]
xref:nng_strerror.3.adoc[nng_strerror(3)],
xref:nng_dialer.5.adoc[nng_dialer(5)],
xref:nng.7.adoc[nng(7)]