= nng_alloc(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_stats_get - get statistics snapshot

== SYNOPSIS

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

typedef struct nng_stat nng_stat;

int nng_stats_get(nng_stat **statsp)
----

== DESCRIPTION

The `nng_stat_get()` function attempts to obtain a snapshot of all the
various diagnostic statistics that are present in the system.

NOTE: The process of collecting statistics is designed to have minimal
impact on the system, but there is still some impact.

The statistics are organized as a tree, rooted with a parent
statistic of type `NNG_STAT_SCOPE` that carries no value, and which
has an empty name.
This parent statistic is returned through the _statsp_ pointer.

The `<<nng_stat_child.3#,nng_stat_child()>>` and
`<<nng_stat_next.3#,nng_stat_next()>>` function can be used to
iterate over the the tree.

When no longer needed, the statistics can be freed with the
`<<nng_stats_free.3#,nng_stats_free()>>` function, but that
function must be called only with the root statistic that is returned
through the _statsp_ pointer.

NOTE: The values of individual statistics are guaranteed to be atomic,
but due the way statistics are collected there can be discrepancies between them at certain times.
For example, statistics counting bytes and messages received may not
reflect the same number of messages, depending on when the snapshot is taken.
This potential inconsistency arises as a result of optimizations to minimize
the impact of statistics on actual operations.

NOTE: The names, values, and semantics of statistics provided may change
from release to release.
These are provided for informational and debugging use only, and applications
should not rely on the presence, names, or meanings of any individual statistics.

== RETURN VALUES

This function returns a pointer to the allocated memory on success,
and `NULL` otherwise.

== ERRORS

[horizontal]
`NNG_ENOMEM`:: Insufficient free memory to collect statistics.
`NNG_ENOTSUP`:: Statistics are not supported (compile time option).

== SEE ALSO

[.text-left]
<<nng_stats_free.3#,nng_stats_free(3)>>,
<<nng_stat_child.3#,nng_stat_child(3)>>,
<<nng_stat_desc.3#,nng_stat_desc(3)>>,
<<nng_stat_name.3#,nng_stat_name(3)>>,
<<nng_stat_next.3#,nng_stat_next(3)>>,
<<nng_stat_string.3#,nng_stat_string(3)>>,
<<nng_stat_type.3#,nng_stat_type(3)>>,
<<nng_stat_timestamp.3#,nng_stat_timestamp(3)>>,
<<nng_stat_unit.3#,nng_stat_unit(3)>>,
<<nng_stat_value.3#,nng_stat_value(3)>>,
<<nng_stat.5#,nng_stat(5)>>,
<<nng.7#,nng(7)>>
