.. include:: <mmlalias.txt>


OS Primitives: Threads
======================

.. topic:: Documentation

   * :doc:`../code/threads`
   * `Zephyr:
     <https://docs.zephyrproject.org/latest/kernel/services/threads/index.html>`__

Threads Basics
--------------

.. topic:: See also

   * :doc:`/trainings/material/soup/linux/sysprog/posix-threads/index`

* Scheduled by the OS: timeslices
* Zephyr: cooperative vs. preemptive threads
* One stack per thread
* Threads may *block* on OS primitives like a :doc:`mutex
  <../code/locking>` or :doc:`message queue <../code/communication>`.
* Priorities: when a higher priority thread becomes *runnable*, the
  currently running thread is *suspended*, and a *context switch* is
  made to run the higher priority thread

Main Thread
-----------

* One thread is always there, implicitly created
* |longrightarrow| Main thread
* Zephyr: runs at highest priority
* |longrightarrow| Careful

.. literalinclude:: code/mainthread.cpp
   :caption: :download:`code/mainthread.cpp`
   :language: c++

jjj Handler Threads
-------------------