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zephyr/samples/kernel/condition_variables/simple
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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 

.. _samples_kernel_simple_condition_variables:

Condition Variables
###################

Overview
********

This sample demonstrates the usage of condition variables in a
multithreaded application. Condition variables are used with a mutex
to signal changing states (conditions) from worker thread to the main
thread. Main thread uses a condition variable to wait for a condition to
become true. Main thread and the worker thread alternate between their
execution based on when the worker thread signals the main thread that is
pending on the condition variable. The sample can be used with any
:ref:`supported board <boards>` and prints the sample output shown to
the console.

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

This application can be built and executed on Native Posix as follows:

.. zephyr-app-commands::
   :zephyr-app: samples/kernel/condition_variables/simple
   :host-os: unix
   :board: native_posix
   :goals: run
   :compact:

To build for another board, change "native_posix" above to that board's name.

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

.. code-block:: console

    [thread 0] working (0/5)
    [thread 1] working (0/5)
    [thread 2] working (0/5)
    [thread 3] working (0/5)
    [thread 4] working (0/5)
    [thread 5] working (0/5)
    [thread 6] working (0/5)
    [thread 7] working (0/5)
    [thread 8] working (0/5)
    [thread 9] working (0/5)
    [thread 10] working (0/5)
    [thread 11] working (0/5)
    [thread 12] working (0/5)
    [thread 13] working (0/5)
    [thread 14] working (0/5)
    [thread 15] working (0/5)
    [thread 16] working (0/5)
    [thread 17] working (0/5)
    [thread 18] working (0/5)
    [thread 19] working (0/5)
    [thread 0] working (1/5)
    [thread 1] working (1/5)
    [thread 2] working (1/5)
    [thread 3] working (1/5)
    [thread 4] working (1/5)
    [thread 5] working (1/5)
    [thread 6] working (1/5)
    [thread 7] working (1/5)
    [thread 8] working (1/5)
    [thread 9] working (1/5)
    [thread 10] working (1/5)
    [thread 11] working (1/5)
    [thread 12] working (1/5)
    [thread 13] working (1/5)
    [thread 14] working (1/5)
    [thread 15] working (1/5)
    [thread 16] working (1/5)
    [thread 17] working (1/5)
    [thread 18] working (1/5)
    [thread 19] working (1/5)
    [thread zephyr_app_main] done is 0 which is < 20 so waiting on cond
    [thread 0] working (2/5)
    [thread 1] working (2/5)
    [thread 2] working (2/5)
    [thread 3] working (2/5)
    [thread 4] working (2/5)
    [thread 5] working (2/5)
    [thread 6] working (2/5)
    [thread 7] working (2/5)
    [thread 8] working (2/5)
    [thread 9] working (2/5)
    [thread 10] working (2/5)
    [thread 11] working (2/5)
    [thread 12] working (2/5)
    [thread 13] working (2/5)
    [thread 14] working (2/5)
    [thread 15] working (2/5)
    [thread 16] working (2/5)
    [thread 17] working (2/5)
    [thread 18] working (2/5)
    [thread 19] working (2/5)
    [thread 0] working (3/5)
    [thread 1] working (3/5)
    [thread 2] working (3/5)
    [thread 3] working (3/5)
    [thread 4] working (3/5)
    [thread 5] working (3/5)
    [thread 6] working (3/5)
    [thread 7] working (3/5)
    [thread 8] working (3/5)
    [thread 9] working (3/5)
    [thread 10] working (3/5)
    [thread 11] working (3/5)
    [thread 12] working (3/5)
    [thread 13] working (3/5)
    [thread 14] working (3/5)
    [thread 15] working (3/5)
    [thread 16] working (3/5)
    [thread 17] working (3/5)
    [thread 18] working (3/5)
    [thread 19] working (3/5)
    [thread 0] working (4/5)
    [thread 1] working (4/5)
    [thread 2] working (4/5)
    [thread 3] working (4/5)
    [thread 4] working (4/5)
    [thread 5] working (4/5)
    [thread 6] working (4/5)
    [thread 7] working (4/5)
    [thread 8] working (4/5)
    [thread 9] working (4/5)
    [thread 10] working (4/5)
    [thread 11] working (4/5)
    [thread 12] working (4/5)
    [thread 13] working (4/5)
    [thread 14] working (4/5)
    [thread 15] working (4/5)
    [thread 16] working (4/5)
    [thread 17] working (4/5)
    [thread 18] working (4/5)
    [thread 19] working (4/5)
    [thread 0] done is now 1. Signalling cond.
    [thread zephyr_app_main] wake - cond was signalled.
    [thread zephyr_app_main] done is 1 which is < 20 so waiting on cond
    [thread 1] done is now 2. Signalling cond.
    [thread zephyr_app_main] wake - cond was signalled.
    [thread zephyr_app_main] done is 2 which is < 20 so waiting on cond
    [thread 2] done is now 3. Signalling cond.
    [thread zephyr_app_main] wake - cond was signalled.
    [thread zephyr_app_main] done is 3 which is < 20 so waiting on cond
    [thread 3] done is now 4. Signalling cond.
    [thread zephyr_app_main] wake - cond was signalled.
    [thread zephyr_app_main] done is 4 which is < 20 so waiting on cond
    [thread 4] done is now 5. Signalling cond.
    [thread zephyr_app_main] wake - cond was signalled.
    [thread zephyr_app_main] done is 5 which is < 20 so waiting on cond
    [thread 5] done is now 6. Signalling cond.
    [thread zephyr_app_main] wake - cond was signalled.
    [thread zephyr_app_main] done is 6 which is < 20 so waiting on cond
    [thread 6] done is now 7. Signalling cond.
    [thread zephyr_app_main] wake - cond was signalled.
    [thread zephyr_app_main] done is 7 which is < 20 so waiting on cond
    [thread 7] done is now 8. Signalling cond.
    [thread zephyr_app_main] wake - cond was signalled.
    [thread zephyr_app_main] done is 8 which is < 20 so waiting on cond
    [thread 8] done is now 9. Signalling cond.
    [thread zephyr_app_main] wake - cond was signalled.
    [thread zephyr_app_main] done is 9 which is < 20 so waiting on cond
    [thread 9] done is now 10. Signalling cond.
    [thread zephyr_app_main] wake - cond was signalled.
    [thread zephyr_app_main] done is 10 which is < 20 so waiting on cond
    [thread 10] done is now 11. Signalling cond.
    [thread zephyr_app_main] wake - cond was signalled.
    [thread zephyr_app_main] done is 11 which is < 20 so waiting on cond
    [thread 11] done is now 12. Signalling cond.
    [thread zephyr_app_main] wake - cond was signalled.
    [thread zephyr_app_main] done is 12 which is < 20 so waiting on cond
    [thread 12] done is now 13. Signalling cond.
    [thread zephyr_app_main] wake - cond was signalled.
    [thread zephyr_app_main] done is 13 which is < 20 so waiting on cond
    [thread 13] done is now 14. Signalling cond.
    [thread zephyr_app_main] wake - cond was signalled.
    [thread zephyr_app_main] done is 14 which is < 20 so waiting on cond
    [thread 14] done is now 15. Signalling cond.
    [thread zephyr_app_main] wake - cond was signalled.
    [thread zephyr_app_main] done is 15 which is < 20 so waiting on cond
    [thread 15] done is now 16. Signalling cond.
    [thread zephyr_app_main] wake - cond was signalled.
    [thread zephyr_app_main] done is 16 which is < 20 so waiting on cond
    [thread 16] done is now 17. Signalling cond.
    [thread zephyr_app_main] wake - cond was signalled.
    [thread zephyr_app_main] done is 17 which is < 20 so waiting on cond
    [thread 17] done is now 18. Signalling cond.
    [thread zephyr_app_main] wake - cond was signalled.
    [thread zephyr_app_main] done is 18 which is < 20 so waiting on cond
    [thread 18] done is now 19. Signalling cond.
    [thread zephyr_app_main] wake - cond was signalled.
    [thread zephyr_app_main] done is 19 which is < 20 so waiting on cond
    [thread 19] done is now 20. Signalling cond.
    [thread zephyr_app_main] wake - cond was signalled.
    [thread zephyr_app_main] done == 20 so everyone is done