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Producer Consumer Problem using semaphores

Nice Narwhal answered on July 16, 2023 Popularity 6/10 Helpfulness 1/10

answer Producer Consumer Problem using semaphores

Producer Consumer Problem using semaphores

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#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <semaphore.h>

#define MAX 10

int buffer[MAX];
int fill = 0;
int use = 0;

sem_t empty;
sem_t full;
sem_t mutex;

void put(int value) {
    buffer[fill] = value; // Line F1
    fill = (fill + 1) % MAX; // Line F2
}

int get() {
    int tmp = buffer[use]; // Line G1
    use = (use + 1) % MAX; // Line G2
    return tmp;
}

void* producer(void* arg) {
    int loops = *((int*)arg);
    for (int i = 0; i < loops; i++) {
        sem_wait(&empty); // Line P1
        sem_wait(&mutex); // Line P1.5 (MUTEX HERE)
        put(i); // Line P2
        sem_post(&mutex); // Line P2.5 (AND HERE)
        sem_post(&full); // Line P3
    }
    pthread_exit(NULL);
}

void* consumer(void* arg) {
    int loops = *((int*)arg);
    for (int i = 0; i < loops; i++) {
        sem_wait(&full); // Line C1
        sem_wait(&mutex); // Line C1.5 (MUTEX HERE)
        int tmp = get(); // Line C2
        sem_post(&mutex); // Line C2.5 (AND HERE)
        sem_post(&empty); // Line C3
        printf("%d\n", tmp);
    }
    pthread_exit(NULL);
}

int main(int argc, char* argv[]) {
    if (argc != 2) {
        printf("Usage: %s <loops>\n", argv[0]);
        return 1;
    }

    int loops = atoi(argv[1]);

    sem_init(&empty, 0, MAX); // MAX are empty
    sem_init(&full, 0, 0); // 0 are full
    sem_init(&mutex, 0, 1); // Initialize mutex to 1

    pthread_t prod_thread, cons_thread;

    pthread_create(&prod_thread, NULL, producer, &loops);
    pthread_create(&cons_thread, NULL, consumer, &loops);

    pthread_join(prod_thread, NULL);
    pthread_join(cons_thread, NULL);

    sem_destroy(&empty);
    sem_destroy(&full);
    sem_destroy(&mutex);

    return 0;
}

Popularity 6/10 Helpfulness 1/10 Language whatever

Source: chat.openai.com

Tags: producer-consumer using whatever

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Contributed on Jul 16 2023

Nice Narwhal

0 Answers Avg Quality 2/10

Producer Consumer Problem using semaphores

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