Listing 9: The Test Harness
#include "calculator.hpp"
#include "printer.hpp"
#include <iostream>
#include <stdio.h>

calculator *calc = NULL;

void * runPrinter(void *arg)
{
  printer *prn = (printer *)arg;
  prn->printPowersOfTwo(calc); 
}

void * runCalculator(void *arg)
{
  calculator *calc = (calculator *)arg;
  calc->calcPowersOfTwo();
}

void main()
{
  thread_t prn1Tid, prn2Tid, prn3Tid, prn4Tid, calcTid;

  calc = new calculator();
  thr_create(NULL, 0, runCalculator, calc, 0, &calcTid);

  printer *prn1 = new printer();
  prn1->printerName = "First Printer";
  thr_create(NULL, 0, runPrinter, prn1, 0, &prn1Tid);
  printer *prn2 = new printer();
  prn2->printerName = "Second Printer";
  thr_create(NULL, 0, runPrinter, prn2, 0, &prn2Tid);
  printer *prn3 = new printer();
  prn3->printerName = "Third Printer";
  thr_create(NULL, 0, runPrinter, prn3, 0, &prn3Tid);
  printer *prn4 = new printer();
  prn4->printerName = "Fourth Printer";
  thr_create(NULL, 0, runPrinter, prn4, 0, &prn4Tid);
  
  // Wait for the calculator thread to finish
  thr_join(calcTid, NULL, NULL);

  // Signal the printer threads
  thr_kill(prn1Tid, SIGUSR1);
  thr_kill(prn2Tid, SIGUSR1);
  thr_kill(prn3Tid, SIGUSR1);
  thr_kill(prn4Tid, SIGUSR1);

  // Wait for the printer threads to complete
  char wait;
  cin >> wait;
}