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()
and
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()
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. |
This function returns a pointer to the allocated memory on success,
and NULL
otherwise.
NNG_ENOMEM
|
Insufficient free memory to collect statistics. |
NNG_ENOTSUP
|
Statistics are not supported (compile time option). |