C

mutex c

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

#ifndef NUM_THREADS
#define NUM_THREADS 4
#endif

int shared = 0;
pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;

void *func3(void* param)
{
    pthread_mutex_lock(&mutex);
    printf("Incrementing the shared variable...
");
    for (int i = 0; i < 10000; ++i) {
        shared += 1;
    }
    pthread_mutex_unlock(&mutex);
    return 0;
}

int main()
{
    pthread_t threads[NUM_THREADS];

    for (int i = 0; i < NUM_THREADS; ++i) {
        pthread_create(&threads[i], NULL, func3, NULL);
    }

    for (int i = 0; i < NUM_THREADS; ++i) {
        pthread_join(threads[i], NULL);
    }

    printf("%d
", shared);
    exit(EXIT_SUCCESS);
}