zephyr

History

James Harris b10428163a kernel: sem: add K_SEM_MAX_LIMIT Currently there is no way to distinguish between a caller explicitly asking for a semaphore with a limit that happens to be `UINT_MAX` and a semaphore that just has a limit "as large as possible". Add `K_SEM_MAX_LIMIT`, currently defined to `UINT_MAX`, and akin to `K_FOREVER` versus just passing some very large wait time. In addition, the `k_sem_*` APIs were type-confused, where the internal data structure was `uint32_t`, but the APIs took and returned `unsigned int`. This changes the underlying data structure to also use `unsigned int`, as changing the APIs would be a (potentially) breaking change. These changes are backwards-compatible, but it is strongly suggested to take a quick scan for `k_sem_init` and `K_SEM_DEFINE` calls with `UINT_MAX` (or `UINT32_MAX`) and replace them with `K_SEM_MAX_LIMIT` where appropriate. Signed-off-by: James Harris <james.harris@intel.com>		2021-03-05 08:13:53 -06:00
..
src	kernel: sem: add K_SEM_MAX_LIMIT	2021-03-05 08:13:53 -06:00
CMakeLists.txt
prj.conf
README.rst
sample.yaml	samples: cpp_synchronization: filter for integration	2020-07-30 08:00:03 -04:00

README.rst

.. _cpp_synchronization:

C++ Synchronization
###################

Overview
********
The sample project illustrates usage of pure virtual class, member
functions with different types of arguments, global objects constructor
invocation.

A simple application demonstrates basic sanity of the kernel.  The main thread
and a cooperative thread take turns printing a greeting message to the console,
and use timers and semaphores to control the rate at which messages are
generated. This demonstrates that kernel scheduling, communication, and
timing are operating correctly.

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

This kernel project outputs to the console.  It can be built and executed
on QEMU as follows:

.. zephyr-app-commands::
   :zephyr-app: samples/cpp_synchronization
   :host-os: unix
   :board: qemu_x86
   :goals: run
   :compact:

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

.. code-block:: console

     Create semaphore 0x001042b0
     Create semaphore 0x001042c4
     main: Hello World!
     coop_thread_entry: Hello World!
     main: Hello World!
     coop_thread_entry: Hello World!
     main: Hello World!
     coop_thread_entry: Hello World!
     main: Hello World!
     coop_thread_entry: Hello World!
     main: Hello World!
     coop_thread_entry: Hello World!
     main: Hello World!
     coop_thread_entry: Hello World!
     main: Hello World!
     coop_thread_entry: Hello World!
     main: Hello World!
     coop_thread_entry: Hello World!
     main: Hello World!
     coop_thread_entry: Hello World!
     main: Hello World!

     <repeats endlessly>

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