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

void* worker(void* arg) {
    int *a_x = arg;
    while(*a_x < 100) {
        (*a_x)++;
    }
    printf("increment finished\n");
    return NULL;
}

// GOAL:  Increment x and y to 100, using only ++.  Yes, this is silly.

int main() {
    int x = 0, y = 0;
    printf("x: %d, y: %d\n", x, y);

    pthread_t t1;  // This is an "opaque" objects -- none of your biz
    int status = pthread_create(&t1, NULL, worker, &x);  // also runs it
    // like calling worker(&x)
    if(status != 0) {
        return EXIT_FAILURE;
    }

    pthread_t t2;
    status = pthread_create(&t2, NULL, worker, &y);
    if(status != 0) {
        return EXIT_FAILURE;
    }

    // Three threads are active now:  main thread, t1, and t2

    // Wait for t1 to finish, and then join (terminate the thread nicely)
    pthread_join(t1, NULL);

    /* // If t2 finished before t1 finished, then t2 is waiting now. */
    /* pthread_join(t2, NULL); */

    printf("x: %d, y: %d\n", x, y);
    return 0;
}
    /*
    // temporary:
    int num_threads = 2;
    pthread_t* threads = malloc(sizeof(*threads) * num_threads);
    pthread_create(&threads[0], NULL, worker, &y); // TODO: check if returns 0
    */