/* 范例：9-24 */
#include <fcntl.h>
#include <io.h>
#include <stdio.h>
#include <stdlib.h>
void main(int argc,char *argv[])
{
  int file1,file2;
  char buf[512];
  if((file1 = open(argv[1],O_RDONLY))==-1)
  {
    printf("Read file %s Error!\n",argv[1]);
    exit(1);
  }
  if((file2 = open(argv[2], O_WRONLY|O_CREAT))==-1)
  {
    printf("Create file %s Error!\n",argv[2]);
    exit(1);
  }
  while(read(file1,buf,512)>0)
    write(file2,buf,512);

  close(file1);
  close(file2);
}

程序執行結果：
D:\TC>p9-24 xx.txt out.txt