02 Logging

Overview

This sample demonstrates the use of Zephyr’s logging subsystem. It shows how to use different log levels and print various data types to the console.

This sample is useful for:

Understanding log levels (ERR, WRN, INF, DBG)
Setting log level via Kconfig
Learning about logging backends
Observing that DBG messages include function names

Key Features:

Demonstrates printk() vs logging macros
Shows different data types (integers, strings, pointers)
Includes hexdump functionality

Building

This application can be built and executed on native_sim as follows:

host:~$ west build -b native_sim samples/02_logging -p
host:~$ west build -t run

To build for a real board (e.g., reel_board@2), use:

host:~$ west build -b reel_board@2 samples/02_logging -p
host:~$ west flash

Sample Output

*** Booting Zephyr OS build v4.3.0 ***
Hello World! native_sim
[00:00:00.001,691] <err> logging_sample: error string
[00:00:00.001,843] <dbg> logging_sample: main: debug string
[00:00:00.001,859] <inf> logging_sample: info string
[00:00:00.001,874] <dbg> logging_sample: main: int8_t 1, uint8_t 2
[00:00:00.001,887] <dbg> logging_sample: main: int16_t 16, uint16_t 17
[00:00:00.001,899] <dbg> logging_sample: main: int32_t 32, uint32_t 33
[00:00:00.001,921] <dbg> logging_sample: main: int64_t 64, uint64_t 65
[00:00:00.001,956] <dbg> logging_sample: main: char !
[00:00:00.002,383] <dbg> logging_sample: main: s str static str c str
[00:00:00.002,567] <dbg> logging_sample: main: d str dynamic str
[00:00:00.002,607] <dbg> logging_sample: main: mixed str dynamic str --- ...
[00:00:00.002,640] <dbg> logging_sample: main: mixed c/s ! static str ...
[00:00:00.002,653] <dbg> logging_sample: main: pointer 0x5c3e
[00:00:00.002,674] <dbg> logging_sample: main: HeXdUmP!
                                  48 45 58 44 55 4d 50 21  20 23 40  |HEXDUMP!  #@

Exit native_sim by pressing CTRL+C.