main.c

#define LOG_PV(func, sem, proc) \
printf("["#proc"] before "#func"("#sem") = %d\n", sem_getval(sem));\
func(sem);\
printf("["#proc"] after "#func"("#sem") = %d\n", sem_getval(sem));

#define LOG_P(sem, proc) \
LOG_PV(P, sem, proc)

#define LOG_V(sem, proc) \
LOG_PV(V, sem, proc)

//Producer process
if(pid > 0)
{
    while(1)
    {
        LOG_P(emptyShelf, Waiter);

        LOG_P(mutex, Waiter);
        waiter_as_producer();
        LOG_V(mutex, Waiter);
        
        LOG_V(orderOnShelf, Waiter);
        
        LOG_P(pizzaOnShelf, Waiter);
        
        LOG_P(mutex, Waiter);
        waiter_as_consumer();
        LOG_V(mutex, Waiter);
        
        LOG_V(emptyShelf, Waiter);
    }
}

if(pid == 0)
{
    while(1)
    {
        LOG_P(orderOnShelf, Cook); // make sure there is an order on shelf
        LOG_P(mutex, Cook); //permission to work
        cooker_as_consumer(); // take order and put pizza on shelf
        LOG_V(mutex, Cook); //release permission
        LOG_V(pizzaOnShelf, Cook); // pizza is now on shelf
    }
}

sem.h

int sem_getval(int semid) {
    union semun s;
    return semctl(semid, 0, GETVAL, s);
}