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= nng_stream_get(3str)
//
// Copyright 2024 Staysail Systems, Inc. <info@staysail.tech>
// Copyright 2018 Capitar IT Group BV <info@capitar.com>
// Copyright 2019 Devolutions <info@devolutions.net>
//
// 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_stream_get - get option from byte stream
== SYNOPSIS
[source, c]
----
#include <nng/nng.h>
int nng_stream_get_bool(nng_stream *s, const char *opt, bool *valp);
int nng_stream_get_int(nng_stream *s, const char *opt, int *valp);
int nng_stream_get_ms(nng_stream *s, const char *opt, nng_duration *valp);
int nng_stream_get_size(nng_stream *s, const char *opt, size_t *valp);
int nng_stream_get_addr(nng_stream *s, const char *opt, nng_sockaddr *valp);
int nng_stream_get_string(nng_stream *s, const char *opt, char **valp);
int nng_stream_get_uint64(nng_stream *s, const char *opt, uint64_t *valp);
----
== DESCRIPTION
The `nng_stream_get` functions are used to retrieve option values for the
xref:nng_stream.5.adoc[byte stream] _conn_.
The actual options that may be retrieved in this way vary.
A number of them are documented in
xref:nng_options.5.adoc[nng_options(5)] and additional linked documents.
=== Forms
In all of these forms, the option _opt_ is retrieved from the connected
byte stream _s_.
The forms vary based on the type of the option they take.
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.
`nng_stream_get_bool()`::
This function is for options which take a Boolean (`bool`).
`nng_stream_get_int()`::
This function is for options which take an integer (`int`).
`nng_stream_get_ms()`::
This function is used to retrieve time
xref:nng_duration.5.adoc[durations]
(such as timeouts), stored as a number of milliseconds.
(The special value ((`NNG_DURATION_INFINITE`)) means an infinite amount of time, and
the special value ((`NNG_DURATION_DEFAULT`)) means a context-specific default.)
`nng_stream_get_size()`::
This function is used to retrieve a size,
typically for buffer sizes, message maximum sizes, and similar options.
`nng_stream_get_addr()`::
This function is used to retrieve a
xref:nng_sockaddr.5.adoc[socket address].
`nng_stream_get_string()`::
This function is used to retrieve a `NULL`-terminated string.
This string is created from the source using
xref:nng_strdup.3.adoc[`nng_strdup()`]
and consequently must be freed by the caller using
xref:nng_strfree.3.adoc[`nng_strfree()`] when it is no longer needed.
`nng_stream_get_uint64()`::
This function is used to retrieve a 64-bit unsigned value.
This is typically used for identifiers, network
numbers, and similar options.
== RETURN VALUES
This function returns 0 on success, and non-zero otherwise.
== ERRORS
[horizontal]
`NNG_ECLOSED`:: The connection is closed.
`NNG_EINVAL`:: There was insufficient space to receive the object.
The amount of data actually needed is returned in _sizep_.
`NNG_ENOTSUP`:: The option is not supported.
`NNG_EWRITEONLY`:: The option may not read.
== SEE ALSO
[.text-left]
xref:nng_strerror.3.adoc[nng_strerror(3)],
xref:nng_options.5.adoc[nng_options(5)],
xref:nng_ipc_options.5.adoc[nng_ipc_options(5)],
xref:nng_tcp_options.5.adoc[nng_tcp_options(5)],
xref:nng_tls_options.5.adoc[nng_tls_options(5)],
xref:nng_stream.5.adoc[nng_stream(5)]
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