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

// User defined arguments to thread function.
typedef struct 
{
    const char* msg;
    int sleepSecs;
} thread_creation_info_t;


// Thread main function.
void* Child(void* args) 
{
    thread_creation_info_t* info = (thread_creation_info_t*) args;
    size_t i;

    for (i = 0; i < 100; ++i) {
        printf(" %s ", info->msg); 
        sleep(info->sleepSecs);
    }
    return NULL;
}

int main(int argc, char* argv[])
{
    #define SLEEP_SECS 1

    pthread_t child_thread1;
    pthread_t child_thread2;
    thread_creation_info_t info1 = { "+", SLEEP_SECS };
    thread_creation_info_t info2 = { "-", SLEEP_SECS };

    if (pthread_create(&child_thread1, NULL, &Child, &info1) != 0) {
        fprintf(stderr, "Creation of thread1 failed.\n");
        return -1;
    }

    if (pthread_create(&child_thread2, NULL, &Child, &info2) != 0) {
        fprintf(stderr, "Creation of thread2 failed.\n");
        return -1;
    }

    // Wait until both threads have finished.
    pthread_join(child_thread1, NULL);
    pthread_join(child_thread2, NULL);

    return 0;
}