C Program to implement Multi-threaded program

C Program to implement Multi-threaded program

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

#define NUM_THREADS 2

/* create thread argument struct for thr_func() */
typedef struct _thread_data_t {
    int tid;
    double stuff;
} thread_data_t;

/* thread function */
void *thr_func(void *arg) {
    thread_data_t *data = (thread_data_t *)arg;

    fprintf(stdout, "hello from thr_func, thread id: %d\n", data->tid);

    pthread_exit(NULL);
}

int main(int argc, char **argv) {
    pthread_t thr[NUM_THREADS];
    int i, rc;
    /* create a thread_data_t argument array */
    thread_data_t thr_data[NUM_THREADS];

  
  /* create threads */
    for (i = 0; i < NUM_THREADS; ++i) {
        thr_data[i].tid = i;
        if ((rc = pthread_create(&thr[i], NULL, thr_func, &thr_data[i]))) {
            fprintf(stderr, "error: pthread_create, rc: %d\n", rc);
            return EXIT_FAILURE;
        }
    }
    /* block until all threads complete */
    for (i = 0; i < NUM_THREADS; ++i) {
        pthread_join(thr[i], NULL);
    }

    return EXIT_SUCCESS;
}

 

output:

gcc thread.c -lpthread

neelkanth_surekha#ps -elfT | grep a.out
0 S neelkan+  3273  3273  2526  0  80   0 - 22112 futex_ 01:37 pts/19   00:00:00 ./a.out
1 R neelkan+  3273  3274  2526 99  80   0 - 22112 -      01:37 pts/19   00:00:06 ./a.out
1 R neelkan+  3273  3275  2526 99  80   0 - 22112 -      01:37 pts/19   00:00:06 ./a.out
0 S neelkan+  3277  3277  2526  0  80   0 -  3556 pipe_w 01:37 pts/19   00:00:00 grep --color=auto a.out