= nng_dialer_setopt(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_setopt - set dialer option

== SYNOPSIS

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

int nng_dialer_setopt(nng_dialer d, const char *opt, const void *val,
    size_t valsz);

int nng_dialer_setopt_int(nng_dialer d, const char *opt, int ival);

int nng_dialer_setopt_ms(nng_dialer d, const char *opt, nng_duration dur);

int nng_dialer_setopt_ptr(nng_dialer d, const char *opt, void *ptr);

int nng_dialer_setopt_size(nng_dialer d, const char *opt, size_t z);

int nng_dialer_setopt_string(nng_dialer d, const char *opt, const char *str);

int nng_dialer_setopt_uint64(nng_dialer d, const char *opt, uint64_t u64);
-----------

== DESCRIPTION

The `nng_dialer_setopt()` functions are used to configure options for
the dialer _d_. The actual options that may be configured in this way
vary, and are documented in the <<nng_setopt#,nng_setopt(3)>> manual.
Additionally some transport-specific options are documented with the
transports themselves.

In all of these forms, the option _opt_ is configured on the dialer _d_.

The details of the type, size, and semantics of the option will depend
on the actual option, and will be documented with the option itself.

The first form of this function, `nng_dialer_setopt()`, can be used to
configure any arbitrary data.
The _val_ pointer addresses the data to copy, and _valsz_ is the
size of the objected located at _val_.

Generally, it will be easier to use one of the typed forms instead.

The second form, `nng_dialer_setopt_int()`,
is for options which take an integer (or boolean).  The _ival_
is passed to the option.  For booleans pass either 0 (false) or 1 (true).

The third form, `nng_dialer_setopt_ms()`, is used to configure time durations
(such as timeouts).
The duration _dur_ is an integer number of milliseconds.  (The special value
`NNG_DUR_INFINITE` means an infinite amount of time.)

The fourth form, `nng_dialer_setopt_ptr()`, is used to pass a
pointer _ptr_ to structured data.  The data referenced by _ptr_ is
generally managed by other functions.
For example, TLS configuration objects
(<<nng_tls_config_alloc#,nng_tls_config_alloc(3)>>) can be passed this way.
Note that this form is somewhat special in that the object is generally
not copied, but instead the *pointer* to the object is copied.

The fifth form, `nng_dialer_setopt_size()`, is used to pass a size
specified by _z_, typically for buffer sizes, message maximum sizes, and
similar options.

The sixth form, `nng_dialer_setopt_string()`, is used to pass a string
_str_.  Strings passed this way must be legal UTF-8 or ASCII strings, terminated
with a `NUL` (`\0`) byte.  (Other constraints may apply as well, see the
documentation for _opt_ for details.)

The seventh form, `nng_dialer_setopt_uint64()`, is used to configure
the 64-bit unsigned value in _u64_.  This is typically used for options
related to identifiers, network numbers, and similar.

NOTE: Once a dialer has started, it is generally not possible to change
it's configuration.

== RETURN VALUES

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

== ERRORS

`NNG_ECLOSED`:: Parameter _d_ does not refer to an open dialer.
`NNG_EINVAL`:: The value being passed is invalid.
`NNG_ENOTSUP`:: The option _opt_ is not supported.
`NNG_EREADONLY`:: The option _opt_ is read-only.
`NNG_ESTATE`:: The dialer _d_ is already started.

== SEE ALSO

<<nng_dial#,nng_dial(3)>>,
<<nng_dialer_create#,nng_dialer_create(3)>>
<<nng_dialer_getopt#,nng_dialer_getopt(3)>>
<<nng_setopt#,nng_setopt(3)>>,
<<nng_strerror#,nng_strerror(3)>>,
<<nng#,nng(7)>>
