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Prepend the text 'cmake_minimum_required(VERSION 3.8.2)' into the application and test build scripts. Modern versions of CMake will spam users with a deprecation warning when the toplevel CMakeLists.txt does not specify a CMake version. This is documented in bug #8355. To resolve this we include a cmake_minimum_required() line into the toplevel build scripts. Additionally, cmake_minimum_required is invoked from within boilerplate.cmake. The highest version will be enforced. This patch allows us to afterwards change CMake policy CMP000 from OLD to NEW which in turn finally rids us of the verbose warning. The extra boilerplate is considered more acceptable than the verbosity of the CMP0000 policy. Signed-off-by: Sebastian Bøe <sebastian.boe@nordicsemi.no>
.. _dining-philosophers-sample: Dining Philosophers ################### Overview ******** An implementation of a solution to the Dining Philosophers problem (a classic multi-thread synchronization problem). This particular implementation demonstrates the usage of multiple preemptible and cooperative threads of differing priorities, as well as dynamic mutexes and thread sleeping. The philosopher always tries to get the lowest fork first (f1 then f2). When done, he will give back the forks in the reverse order (f2 then f1). If he gets two forks, he is EATING. Otherwise, he is THINKING. Transitional states are shown as well, such as STARVING when the philosopher is hungry but the forks are not available, and HOLDING ONE FORK when a philosopher is waiting for the second fork to be available. Each Philosopher will randomly alternate between the EATING and THINKING state. It is possible to run the demo in coop-only or preempt-only mode. To achieve this, set these values for CONFIG_NUM_COOP_PRIORITIES and CONFIG_NUM_PREEMPT_PRIORITIES in prj.conf: preempt-only: CONFIG_NUM_PREEMPT_PRIORITIES 6 CONFIG_NUM_COOP_PRIORITIES 0 coop-only: CONFIG_NUM_PREEMPT_PRIORITIES 0 CONFIG_NUM_COOP_PRIORITIES 6 In these cases, the philosopher threads will run with priorities 0 to 5 (preempt-only) and -7 to -2 (coop-only). Building and Running ******************** This project outputs to the console. It can be built and executed on QEMU as follows: .. zephyr-app-commands:: :zephyr-app: samples/philosophers :host-os: unix :board: qemu_x86 :goals: run :compact: Sample Output ============= .. code-block:: console Philosopher 0 [P: 3] HOLDING ONE FORK Philosopher 1 [P: 2] HOLDING ONE FORK Philosopher 2 [P: 1] EATING [ 1900 ms ] Philosopher 3 [P: 0] THINKING [ 2500 ms ] Philosopher 4 [C:-1] THINKING [ 2200 ms ] Philosopher 5 [C:-2] THINKING [ 1700 ms ]