/** * @page article_atomic Invoking multiple primitives as a single atomic operation * @{ * It is often necessary to invoke multiple operations involving a * reschedulation as a single atomic operation.
* ChibiOS/RT already implements APIs that perform complex operations, as * example the API @p chSemSignalWait() performs two operations atomically.
* If more complex operations are required in your application then it is * possible to build macro-operations, see the following example: * @code chSysLock(); chSemSignalI(&sem1); chSemSignalI(&sem2); chMtxUnlockS(); chSchRescheduleS(); chSysUnlock(); * @endcode * The above example performs a signal operation on two semaphores, unlocks the * last aquired mutex and finally performs a reschedulation. All the operations * are performed atomically.
* An hypotetical @p chSemSignalSignalWait() operation could be implemented as * follow: * @code chSysLock(); chSemSignalI(&sem1); chSemSignalI(&sem2); chSemWaitS(&Sem3); /* May reschedule or not. */ chSchRescheduleS(); /* This one reschedules if necessary. */ chSysUnlock(); * @endcode * In general multiple I-Class and (non rescheduling) S-Class APIs can be * included and the block is terminated by a rescheduling S-Class API. * An extra @p chSchRescheduleS() can be present at the very end of the block, * it only reschedules if a reschedulation is still required. */ /** @} */