/*
         Using global variables in multiple threads
*/
#include <pthread.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>

int myglobal;

void *thread_function(void *arg)
{
    int i,j;
    for ( i=0; i<20; i++ )
    {
        j=myglobal;
        j=j+1;
        printf(".");
        fflush(stdout);
        sleep(1);
        myglobal=j;
    }
    return NULL;
}

int main(void)
{

    pthread_t mythread;
    int i;

    if ( pthread_create( &mythread, NULL, thread_function, NULL) )
    {
        printf("error creating thread.");
        abort();
    }

    for ( i=0; i<20; i++)
    {
        myglobal=myglobal+1;
        printf("o");
        fflush(stdout);
        sleep(1);
    }

    if ( pthread_join ( mythread, NULL ) )
    {
        printf("error joining thread.");
        abort();
    }

    printf("\nmyglobal equals %d\n",myglobal);

    exit(0);

}