哭：socket错误

dikeniunai

#include <sys/types.h>
#include <sys/socket.h>
/*##include  <sys/socketvar.h>*/
#include <stdio.h>
/*#include "err_exit.h"*/
#define data1 "fine,thanks."
#define data2 "hello,how are you?"
int main(void)
{
int sockets[2],child;
char buf[1024];
if (socketpair(AF_UNIX,SOCK_STREAM,0,sockets) < 0 )
   printf("socketpair error!");
if ((child = fork()) == -1)
   printf("fork error!");
if (child != 0)
{
   close(sockets[0]);
if (read(sockets[1],buf,sizeof(data1)) < 0)
  printf("readding socket err!");
printf("parent process %d received request: %s\n",getpid(),buf);
if(write(sockets[1],data1,sizeof(data1)) < 0)
   printf("writing socket err!");
close(sockets[1]);
}
else
{
close(sockets[1]);
if (write(sockets[0],data2,sizeof(data1)) < 0)
   printf(" write socket 0 err!");
if(read(sockets[0],buf,sizeof(buf)) < 0)
  printf("reading sockets 0 err!");
printf("child proccess %d received answer: %s \n",getpid(),buf);
close(sockets[0]);
}
}

当执行cc -o sock.exe sock.c时，提示：
# cc -o sock.exe sock.c
undefined                       first referenced
symbol                             in file
socketpair                          sock.o
i386ld fatal: Symbol referencing errors. No output written to sock.exe
#
请问这是为什么呀？我应怎么改呀

ssffzz1

socketpair

该函数的头文件包含了吗？

dikeniunai

我看那socket.h文件中有关于socketpair函数的说明
但到于全不全对不对就不知道了，请帮帮忙呀
没人回贴吗？