Embedded Systems Interview Questions

A car company plans to extend its car computer system to offer Bluetooth connectivity with the owner's mobile phone.

Select all correct statements about the properties of such a connection.

(Select all acceptable answers.)

The following part of the C code distributes packets from the input track to the output track:

void* take_and_put(void *arg)
{
    sem_wait(&semaphore);
    take();
    sem_post(&semaphore);

    pthread_mutex_lock(&mutex);
    put();
    pthread_mutex_unlock(&mutex);

    return NULL;
}

Where semaphore and mutex are initialized with:

// int sem_init(sem_t *sem, int pshared, unsigned int value);
sem_init(&semaphore, 0, 3);
// int pthread_mutex_init(pthread_mutex_t *mutex, const pthread_mutexattr_t *attr);
pthread_mutex_init(&mutex, NULL);

If the function take_and_put is repeatedly called by a large number of threads, select correct statements about the take_and_put function.

(Select all acceptable answers.)