/*
 * Simple Thread Example
 * It just creates two threads. Prints messages then exit.
 *
 * APIs used are:
 * 1. pthread_create
 * 2. pthread_attr_init
 * 3. pthread_join
 */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <pthread.h>

#define RETVAL_CHECK(retval,func_name) if(retval) {printf("Function '%s' returned error value %d\n", func_name, retval);}

/*
 * Start routine for the thread.
 * This is thread's starting point. Like main() for process.
 */
void *thread_start_routine( void *ptr )
{
    char *threadName = (char*)ptr;

    printf("%-15s: Called\n", threadName);
    sleep(10);
    printf("%-15s: Completed\n", threadName);

    return 0;
}

/*
 * Main Function
 */
int main()
{
    pthread_t thread1, thread2;
    pthread_attr_t tattr;
    int  retval;

    /* Create Thread with default behavior - null attributes object used */
    retval = pthread_create(&thread1, NULL, thread_start_routine, (void*) "First Thread");
    RETVAL_CHECK(retval,"pthread_create");

    /* Initialized by default thread attributes */
    retval = pthread_attr_init(&tattr);
    RETVAL_CHECK(retval,"pthread_attr_init");
    
    /* Create Thread with default behavior -  attributes object with default setup */
    retval = pthread_create(&thread2, &tattr, thread_start_routine, (void*) "Second Thread");
    RETVAL_CHECK(retval,"pthread_create");


    pthread_join( thread1, NULL);
    sleep(2);
    pthread_join( thread2, NULL); 

    return 0;
}