//example1.cpp
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>
#include <iostream>
using namespace std;
main()
{
  int f1, f2, f3, f4;
  f1 =open("example1.cpp", O_RDONLY);
  cout << "f1 = " << f1 << "\n";
  f2 =open("example1.cpp", O_RDONLY);
  cout << "f2 = " << f2 << "\n";
  f3 =open("example1.cpp", O_RDONLY);
  cout << "f3 = " << f3 << "\n";
  close(f1);
  f4 =open("example1.cpp", O_RDONLY);
  cout << "f4 = " << f4 << "\n";
}