#include <iostream>
#include <unistd.h>
#include <sys/stat.h>
#include <fcntl.h>

using namespace std;
using MyNumberT = int;

int main(){
    int flag1{O_WRONLY|O_CREAT|O_EXCL};
    int flag2{ S_IRUSR | S_IWUSR |S_IRGRP | S_IROTH};

    int fd{open("binaryFile", flag1, flag2)};

    //int fd;
    //if ((fd = open(...)) == -1) {

    if (fd == -1) {
       cerr << "The error number was " << errno << endl;
       perror("\tError open:");
       cerr << "\tDid you remove binaryFile?" << endl;
       return 1;
    }

    cout << endl;
    cout << "FD = " << fd << endl;
    cout << "The size of an int is " << sizeof(int) << endl;
    cout << endl;

    for(MyNumberT i = 0; i < 10; ++i) {
        ssize_t size;

        size = write(fd, &i, sizeof(MyNumberT));
        if (size < 0)  {
           perror("\tError write:");
        }
        cout << "wrote " << i << " in " << sizeof(i) << " bytes." << endl;
    }

    string hello{"Hello World"};
    write(fd, hello.c_str(), sizeof(char)*hello.size());

    close(fd);
    return 0;
}