Which of the following is true about the below code for a reader-writer lock that allows multiple readers in a critical section, but never more than one writer and never a writer and readers at the same time.

typedef struct {
	sem_t rw_mutex;
	sem_t rcount_mutex;
	sem_t writer_waiting;
	int reader_count;
} rw_lock_t;
void rw_lock_init(rw_lock_t *lock) {
	sem_init(&lock->rw_mutex, 0, 1);
	sem_init(&lock->rcount_mutex, 0, 1);
	sem_init(&lock->writer_waiting, 0, 1);
	lock->reader_count = 0;
}
void reader_lock(rw_lock_t *lock) {
	sem_wait(&lock->writer_waiting);
	sem_wait(&lock->rcount_mutex);
	lock->reader_count++;
	if (lock->reader_count == 1) {
		sem_wait(&lock->rw_mutex);
	}
	sem_post(&lock->rcount_mutex);
	sem_post(&lock->writer_waiting);
}
void reader_unlock(rw_lock_t *lock) {
	sem_wait(&lock->rcount_mutex);
	lock->reader_count--;
	if (lock->reader_count == 0) {
		sem_post(&lock->rw_mutex);
	}
	sem_post(&lock->rcount_mutex);
}
void writer_lock(rw_lock_t *lock) {
    sem_wait(&lock->writer_waiting);
    sem_wait(&lock->rw_mutex);
}
void writer_unlock(rw_lock_t *lock) {
    sem_post(&lock->rw_mutex);
    sem_post(&lock->writer_waiting);
}