zephyr/samples/userspace/hello_world_user
Gerard Marull-Paretas 79e6b0e0f6 includes: prefer <zephyr/kernel.h> over <zephyr/zephyr.h>
As of today <zephyr/zephyr.h> is 100% equivalent to <zephyr/kernel.h>.
This patch proposes to then include <zephyr/kernel.h> instead of
<zephyr/zephyr.h> since it is more clear that you are including the
Kernel APIs and (probably) nothing else. <zephyr/zephyr.h> sounds like a
catch-all header that may be confusing. Most applications need to
include a bunch of other things to compile, e.g. driver headers or
subsystem headers like BT, logging, etc.

The idea of a catch-all header in Zephyr is probably not feasible
anyway. Reason is that Zephyr is not a library, like it could be for
example `libpython`. Zephyr provides many utilities nowadays: a kernel,
drivers, subsystems, etc and things will likely grow. A catch-all header
would be massive, difficult to keep up-to-date. It is also likely that
an application will only build a small subset. Note that subsystem-level
headers may use a catch-all approach to make things easier, though.

NOTE: This patch is **NOT** removing the header, just removing its usage
in-tree. I'd advocate for its deprecation (add a #warning on it), but I
understand many people will have concerns.

Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
2022-09-05 16:31:47 +02:00
..
src
CMakeLists.txt
README.rst
prj.conf
sample.yaml

README.rst

.. _hello_world_user:

Hello World
###########

Overview
********
A simple Hello World example that can be used with any supported board and
prints 'Hello World from UserSpace!' to the console.
If unavailable or unconfigured then 'Hello World from privileged mode.'
is printed instead.

This application can be built into modes:

* single thread
* multi threading

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

This project outputs 'Hello World from UserSpace!' to the console.
It can be built and executed on QEMU as follows:

.. zephyr-app-commands::
   :zephyr-app: samples/userspace/hello_world_user
   :host-os: unix
   :board: qemu_riscv32
   :goals: run
   :compact:

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

.. code-block:: console

    Hello World from UserSpace! qemu_riscv32

Exit QEMU by pressing :kbd:`CTRL+A` :kbd:`x`.