produser_consumer.c

// common.h
#define MEMORY_KEY 145
#define SIZE_OF_ARRAY 10

struct wrapper
{
    int array[SIZE_OF_ARRAY];
    sem_t empty;
    sem_t pmutex;
    sem_t cmutex;
    sem_t full;
    int n;
};

// producer.c
#include <semaphore.h>
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <string.h>
#include <fcntl.h>
#include "common.h"

int memoryID;
struct wrapper *memory;
int rc;

void atexit_function() {
    rc = shmctl(memoryID, IPC_RMID, NULL);
    rc = shmdt(memory);
    sem_destroy(&memory->pmutex);
    sem_destroy(&memory->cmutex);
    sem_destroy(&memory->empty);
    sem_destroy(&memory->full);
}

int main() {
    atexit(atexit_function);
    //creating key for shared memory
    srand(time(NULL));
    key_t sharedMemoryKey = ftok(".", MEMORY_KEY);
    if (sharedMemoryKey == -1) {
        perror("ftok():");
        exit(1);
    }

    memoryID = shmget(sharedMemoryKey, sizeof(struct wrapper), IPC_CREAT | 0600);

    if (memoryID == -1) {
        perror("shmget():");
        exit(1);
    }

    memory = shmat(memoryID, NULL, 0);
    if (memory == (void *) -1) {
        perror("shmat():");
        exit(1);
    }

    //initialization

    printf("Initializataion !\n");
    memset(&memory->array, 0, sizeof(memory->array));
    sem_init(&memory->pmutex, 0, 1);
    sem_init(&memory->cmutex, 0, 1);
    sem_init(&memory->empty, 1, SIZE_OF_ARRAY);
    sem_init(&memory->full, 1, 0);
    memory->n = 0;

    if (memoryID == -1) {
        perror("shmget(): ");
        exit(1);
    }


    while (1)
    {
        int r = rand() % 10;
        sem_wait(&memory->empty);
        sem_wait(&memory->pmutex);
        (memory->array)[memory->n]=r;
        memory->n++;
        printf("Adding task\t Value:%d\tNumber of tasks waiting:%d \n",r,memory->n);
        
        usleep(10000);
        sem_post(&memory->pmutex);
        sem_post(&memory->full);
        
    }
}

// consumer.c
#include <semaphore.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include "common.h"
#include <sys/shm.h>

int factorial(int a) {
    if (!a)
        return 1;

    return a * factorial(a - 1);
}

int memoryID;
struct wrapper *memory;

int main() {
    srand(time(NULL));
    key_t sharedMemoryKey = ftok(".",MEMORY_KEY);
    if(sharedMemoryKey==-1)
    {
        perror("ftok():");
        exit(1);
    }
    memoryID=shmget(sharedMemoryKey,sizeof(struct wrapper),0);

    if(memoryID==-1)
    {
        perror("shmget(): ");
        exit(1);
    }

    memory = shmat(memoryID,NULL,0);
    if(memory== (void*)-1)
    {
        perror("shmat():");
        exit(1);
    }

    while (1)
    {
        sem_wait(&memory->full);
        sem_wait(&memory->cmutex);

        memory->n--;
        int n = memory->n;
        int temp = (memory->array)[n];
        printf("Removed item: %d\tFactorial:%d\tNumber of tasks left:%d\n",
            temp, factorial(temp),n);

        usleep(10000);
        sem_post(&memory->cmutex);
        sem_post(&memory->empty);
    }
}