/*
    mtdemo.c by Pieter Suurmond, februari 1, 2003. Copyleft.
    Thanks to Marc Groenewegen, Dinkum Technology, The Netherlands.
*/

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>                 /* For sleep()    */
#include <pthread.h>                /* POSIX threads. */

void* engine_A(void* num)
{
    int     t, n = *((int*)num);    /* Read from shared mem. */
    char    space[8];               /* Is printf() atomic?   */
    
    for (t = 0; t < n; t++)
        space[t] = '\t';
    space[t] = '\0';
    for (t = 0; t < 20; t += n)     /* For 20 seconds. */
        {
        printf("%sengine_A %d: %d\n", space, n, t);
        sleep(n);
        }
    return (void*)NULL;
}

void* engine_B(void* num)           /* Two instances are run. */
{
    int     t, n = *((int*)num);
    char    space[8];

    for (t = 0; t < n; t++)
        space[t] = '\t';
    space[t] = '\0';
    for (t = 0; t < 20; t += n)     /* Also for 20 seconds. */
        {
        printf("%sengine_B %d: %d\n", space, n, t);
        sleep(n);
        }
    return (void*)NULL;
}

int main()
{
    pthread_t   t1, t2, t3;
    void*       retval;
    int         a = 1,
                b = 2,          /* Create 3 threads, one of  */
                c = 3;          /* type A and two of type B. */

    printf("Program mtdemo started.\n");
    if (pthread_create(&t1, NULL, engine_A, (void*)&a) ||
        pthread_create(&t2, NULL, engine_B, (void*)&b) ||
        pthread_create(&t3, NULL, engine_B, (void*)&c))
        {
        printf("pthread_create() failed!\n");
        exit(1);
        }
    printf("Parent created 3 children.\n");
    if (pthread_join(t1, &retval) ||    /* Collapse threads. */
        pthread_join(t2, &retval) ||
        pthread_join(t3, &retval))
        {
        printf("pthread_join() failed!\n");
        exit(1);
        }
    printf("Parent joined threads, done.\n");
    exit(0);
}