zephyr/samples/subsys/nvs
Keith Packard 0b90fd5adf samples, tests, boards: Switch main return type from void to int
As both C and C++ standards require applications running under an OS to
return 'int', adapt that for Zephyr to align with those standard. This also
eliminates errors when building with clang when not using -ffreestanding,
and reduces the need for compiler flags to silence warnings for both clang
and gcc.

Most of these changes were automated using coccinelle with the following
script:

@@
@@
- void
+ int
main(...) {
	...
-	return;
+	return 0;
	...
}

Approximately 40 files had to be edited by hand as coccinelle was unable to
fix them.

Signed-off-by: Keith Packard <keithp@keithp.com>
2023-04-14 07:49:41 +09:00
..
boards
src samples, tests, boards: Switch main return type from void to int 2023-04-14 07:49:41 +09:00
CMakeLists.txt
prj.conf samples: Use immediate logging mode in nvs sample 2022-12-13 17:20:38 +09:00
README.rst
sample.yaml yamllint: fix all yamllint line-length errors 2023-01-04 01:16:45 +09:00

.. _nvs-sample:

NVS: Non-Volatile Storage
#########################

Overview
********

This is a simple application demonstrating use of the NVS
module for non-volatile (flash) storage.  In this application,
a counter is incremented on every reboot and stored in flash,
the application reboots, and the reboot counter data is retrieved.

Requirements
************

* A board with flash support

Building and Running
********************

This sample can be found under :zephyr_file:`samples/subsys/nvs` in the Zephyr tree.

The sample can be build for several platforms, the following commands build the
application for the nrf51dk_nrf51422 board.

.. zephyr-app-commands::
   :zephyr-app: samples/subsys/nvs
   :board: nrf51dk_nrf51422
   :goals: build flash
   :compact:

After flashing the image to the board the output on the console shows the
reboot counter and the boards reboots several times to show the reboot counter
is incremented.

Sample Output
=============

.. code-block:: console

   ***** Booting Zephyr OS v1.12.0-rc1-176-gf091be783 *****
   [fs/nvs] [DBG] nvs_reinit: (Re)Initializing sectors
   [fs/nvs] [DBG] _nvs_sector_init: f->write_location set to c
   [fs/nvs] [INF] nvs_mount: maximum storage length 256 byte
   [fs/nvs] [INF] nvs_mount: write-align: 1, write-addr: c
   [fs/nvs] [INF] nvs_mount: entry sector: 0, entry sector ID: 1
   No address found, adding 192.168.1.1 at id 1
   No key found, adding it at id 2
   No Reboot counter found, adding it at id 3
   Id: 4 not found, adding it
   Longarray not found, adding it as id 4
   Reboot counter history: ...0
   Oldest reboot counter: 0
   Rebooting in ...5...4...3...2...1
   ***** Booting Zephyr OS v1.12.0-rc1-176-gf091be783 *****
   [fs/nvs] [INF] nvs_mount: maximum storage length 256 byte
   [fs/nvs] [INF] nvs_mount: write-align: 1, write-addr: c7
   [fs/nvs] [INF] nvs_mount: entry sector: 0, entry sector ID: 1
   Entry: 1, Address: 192.168.1.1
   Id: 2, Key: ff fe fd fc fb fa f9 f8
   Id: 3, Reboot_counter: 1
   Id: 4, Data: DATA
   Id: 5, Longarray: 0 1 2 3 4 5 6 7 8 9 a b c d e f 10 11 12 13 14 15 16 17 18
   Reboot counter history: ...1...0
   Oldest reboot counter: 0
   Rebooting in ...5...4...3...2...1
   ...