#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#define BUFFERSIZE 4096
#define COPYMODE 0644
void oop(char *, char *);
int main(int argc, char *argv[])
{
int in_fd;
int out_fd;
int n_chars;
char buffer[BUFFERSIZE];
if (argc != 3)
{
fprintf(stderr,"usage:%s source destination/n",*argv);
exit(1);
}
if ((in_fd = open(argv[1], O_RDONLY)) == -1)
oop("cannot open", argv[1]);
if ((out_fd = open(argv[2], O_RDONLY)) == -1)
oop("cannot open", argv[2]);
while ((n_chars = read(in_fd, buffer, BUFFERSIZE)) > 0)
if (write(out_fd, buffer, n_chars) != n_chars)
oop("write error to", argv[2]);
if (n_chars == -1)
oop("read error from", argv[1]);
if (close(in_fd) == -1 || close(out_fd) == -1)
oop("error closing files", "");
}
void oop(char *s1, char *s2)
{
fprintf(stderr,"error:%s",s1);
perror(s2);
exit(1);
}