| :orphan: |
| |
| .. _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 :zephyr:board:`native_sim <native_sim>` as follows: |
| |
| .. zephyr-app-commands:: |
| :zephyr-app: samples/kernel/condition_variables/simple |
| :host-os: unix |
| :board: native_sim |
| :goals: run |
| :compact: |
| |
| To build for another board, change ``native_sim`` 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 |
