程序1.2将标准输入复制到标准输出

 1 #include "apue.h"
 2 
 3 #define BUFFSIZE 4096
 4 
 5 int main()
 6 {
 7     int  n;
 8     char buf[BUFFSIZE];
 9 
10     while ((n = read(STDIN_FILENO, buf, BUFFSIZE)) > 0)
11     {
12         if (write(STDOUT_FILENO, buf, n) != n)
13         {
14             err_sys("write error");
15         }
16     }
17 
18     if (n < 0)
19     {
20         err_sys("read error");
21     }
22 
23     return 0;
24 }