#include <iostream>     // so I don't have to do lo level io everywhere.
#include <unistd.h>     // close, and in general
#include <sys/types.h>  //read
#include <sys/stat.h>   //read
#include <fcntl.h>      //read
#include <stdio.h>      // perror

#include <climits>

using namespace std;

const char * filename = "scratch";

int main() {

    int fd;

    int x  = 7;
    char buf[4];
    int num = -1;

    // more on this open soon.
    fd = open(filename, O_WRONLY | O_CREAT , S_IRWXU | S_IRGRP | S_IROTH );
    if (-1 == fd) {
       perror("Open failed");
       return -1;
    }

    // write the four bytes of the string.
    write(fd,"1234",4);

    // 	write the data stored at x, all of it.
    write(fd, &x,sizeof(int));

    // show the difference between writing an int and the string.
    x = INT_MAX;
    write(fd, &x,sizeof(int));
    write (fd, "2147483647",10);

    // an experiment for byte order.
    x = 0x01020304;
    write(fd, &x,sizeof(int));

    close(fd);

    // now read everything back in.
    
    fd = open(filename, O_RDONLY);

    read(fd, buf, 4);
    read (fd, &num, sizeof(int));

    cout << "The buffer is " << buf << " and the int is " <<  num << endl;

    close(fd);

    return 0;
}