#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

const int BUFF_SIZE = 4096;

int main(int argc, char *argv[])
{
  char *buffer, *ptr;
  int i = 1;

  for (; i < argc; i++)
  {
    int fd = open(argv[i], O_RDONLY);
    int ret, nb_bytes = 1, n;

    if (fd == -1) perror(argv[i]);
    else
    {
      while (nb_bytes > 0)
      {
        buffer = (char *) calloc(BUFF_SIZE, sizeof(char)); 
        nb_bytes = read(fd, buffer, BUFF_SIZE);
        if (nb_bytes == -1)
        {
          perror(argv[i]); 
          break;
        }

        ptr = buffer;
        n = nb_bytes;

        while (n > 0)
        {
          ret = write(STDOUT_FILENO, ptr, n);
          if (ret == -1)
          {
            perror(argv[i]);
            return -1;
          }

          ptr += ret;
          n -= ret;
        }

        free(buffer);
      }

      close(fd);
    }
  }

  return 0;
}