Ejemplo de 2 Threads en C

#include <stdlib.h>
#include <unistd.h>
#include <pthread.h>
#include <stdio.h>
//gcc main.c -o monProgramme -lpthread

void* thread2 (void* arg);
void* thread1 (void* arg);

int main (void)
{
    int val=0;
    pthread_t monthread1;
    pthread_t monthread2;

    pthread_create (&monthread1, NULL, thread1, &val);
    pthread_create (&monthread2, NULL, thread2, &val); /* Création des threads */

    pthread_join (monthread1, NULL);
    pthread_join (monthread2, NULL); /* Attente de la fin des threads */

    printf ("val =%d\n",val);

    return 0;
}

void* thread1 (void* arg)
{
    int *val = arg;
    printf ("thread1 ON \n");
    for (int i=0;i<100;i++){
        (*val)++;
    }

    printf ("thread1 OFF \n");
    pthread_exit(NULL); /* Fin du thread */
}

void* thread2 (void* arg)
{
    int *val = arg;
    printf ("thread2 ON \n");
    for (int i=0;i<100;i++){
        (*val)++;
    }

    printf ("thread2 OFF \n");
    pthread_exit(NULL); /* Fin du thread */

}