.. zephyr:code-sample:: settings
:name: Settings API
:relevant-api: settings settings_rt settings_name_proc
Load and save configuration values using the settings API.
Overview
********
This is a simple application demonstrating use of the settings runtime
configuration module. In this application some configuration values are loaded
from persistent storage and exported to persistent storage using different
settings method. The example shows how to implement module handlers, how to
register them.
Requirements
************
* A board with settings support, for instance: nrf52840dk/nrf52840
* Or qemu_x86 target
Building and Running
********************
This sample can be found under :zephyr_file:`samples/subsys/settings` in
the Zephyr tree.
The sample can be build for several platforms, the following commands build the
application for the qemu_x86.
.. zephyr-app-commands::
:zephyr-app: samples/subsys/settings
:host-os: unix
:board: qemu_x86
:goals: run
:compact:
After running the image to the board the output on the console shows the
settings manipulation messages.
Sample Output
=============
.. code-block:: console
***** Booting Zephyr OS build v2.1.0-rc1-123-g41091eb1d5e0 *****
*** Settings usage example ***
settings subsys initialization: OK.
subtree <alpha> handler registered: OK
subtree <alpha/beta> has static handler
##############
# iteration 0
##############
=================================================
basic load and save using registered handlers
load all key-value pairs using registered handlers
loading all settings under <beta> handler is done
loading all settings under <alpha> handler is done
save <alpha/beta/voltage> key directly: OK.
load <alpha/beta> key-value pairs using registered handlers
<alpha/beta/voltage> = -3025
loading all settings under <beta> handler is done
save all key-value pairs using registered handlers
export keys under <beta> handler
export keys under <alpha> handler
load all key-value pairs using registered handlers
export keys under <beta> handler
export keys under <alpha> handler
=================================================
loading subtree to destination provided by the caller
direct load: <alpha/length/2>
direct load: <alpha/length/1>
direct load: <alpha/length>
direct.length = 100
direct.length_1 = 41
direct.length_2 = 59
=================================================
Delete a key-value pair
immediate load: OK.
<alpha/length> value exist in the storage
delete <alpha/length>: OK.
Can't to load the <alpha/length> value as expected
=================================================
Service a key-value pair without dedicated handlers
<gamma> = 0 (default)
save <gamma> key directly: OK.
...
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