pthread_barrier_t 사용법 (pthread barrier)

// VERY VERY SIMPLE EXAMPLE BELOW !!



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


#define RANGE_WORK_NUM  (5)
#define RANGE_SLEEP     (100000)
#define NUM_THREADS     (4)


typedef struct {
    unsigned int id;
    pthread_barrier_t *bar;
} worker_param_t;


static void* worker(void *carpark_in) {

    worker_param_t *worker_param = (worker_param_t *)carpark_in;
    unsigned int seed, heart_beat = 0;
    unsigned int i = 0;

    printf("[%02u]+worker\r\n", worker_param->id);

    for (;i < rand_r(&seed) % RANGE_WORK_NUM; i++) {
        usleep(rand_r(&seed) % RANGE_SLEEP);
        printf("[%02u] do work... = %u\r\n", worker_param->id, heart_beat++);
    }
    
    pthread_barrier_wait(worker_param->bar);
    printf("[%02u]-worker\r\n", worker_param->id);

    return (NULL);
}


int main(int argc, char *argv[]) {
    unsigned int i;
    worker_param_t worker_param[NUM_THREADS];
    pthread_t workers[NUM_THREADS];
    pthread_barrier_t bar;

    pthread_barrier_init(&bar, NULL, NUM_THREADS);    

    for (i = 0; i < NUM_THREADS; i++) {
        worker_param[i].id = i;
        worker_param[i].bar = &bar;
        pthread_create(&workers[i], NULL, worker, (void *)&worker_param[i]);
    }

    printf("start join\r\n");

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

    printf("---\r\n");
    
    /*Changed from resturn(0) */
    return (EXIT_SUCCESS);
}