转自：http://www.groad.net/bbs/thread-1709-1-1.html
程序说明：
程序里包含服务端和客户端两个程序，它们之间使用 AF_UNIX 实现本机数据流通信。使用 AF_UNIX 域实际上是使用本地 socket 文件来通信。
服务器端代码：
#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <sys/un.h>
#include <unistd.h>
#include <stdlib.h>
int main (int argc, char *argv[])
{
int server_sockfd, client_sockfd;
int server_len, client_len;
struct sockaddr_un server_address; /*声明一个UNIX域套接字结构*/
struct sockaddr_un client_address;
int i, bytes;
char ch_send, ch_recv;
unlink ("server_socket"); /*删除原有server_socket对象*/
/*创建 socket, 通信协议为AF_UNIX, SCK_STREAM 数据方式*/
server_sockfd = socket (AF_UNIX, SOCK_STREAM, 0);
/*配置服务器信息(通信协议)*/
server_address.sun_family = AF_UNIX;
/*配置服务器信息(socket 对象)*/
strcpy (server_address.sun_path, "server_socket");
/*配置服务器信息(服务器地址长度)*/
server_len = sizeof (server_address);
/*绑定 socket 对象*/
bind (server_sockfd, (struct sockaddr *)&server_address, server_len);
/*监听网络,队列数为5*/
listen (server_sockfd, 5);
printf ("Server is waiting for client connect...
");
client_len = sizeof (client_address);
/*接受客户端请求; 第2个参数用来存储客户端地址; 第3个参数用来存储客户端地址的大小*/
/*建立(返回)一个到客户端的文件描述符,用以对客户端的读写操作*/
client_sockfd = accept (server_sockfd, (struct sockaddr *)&server_address, (socklen_t *)&client_len);
if (client_sockfd == -1) {
perror ("accept");
exit (EXIT_FAILURE);
}
printf ("The server is waiting for client data...
");
for (i = 0, ch_send = '1'; i < 5; i++, ch_send++) {
if ((bytes = read (client_sockfd, &ch_recv, 1)) == -1) {
perror ("read");
exit (EXIT_FAILURE);
}
printf ("The character receiver from client is %c
", ch_recv);
sleep (1);
if ((bytes = write (client_sockfd, &ch_send, 1)) == -1) {
perror ("read");
exit (EXIT_FAILURE);
}
}
close (client_sockfd);
unlink ("server socket");
}
客户端代码：
#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <sys/un.h>
#include <unistd.h>
#include <stdlib.h>
int main (int argc, char *argv[])
{
struct sockaddr_un address;
int sockfd;
int len;
int i, bytes;
int result;
char ch_recv, ch_send;
/*创建socket,AF_UNIX通信协议,SOCK_STREAM数据方式*/
if ((sockfd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
perror ("socket");
exit (EXIT_FAILURE);
}
address.sun_family = AF_UNIX;
strcpy (address.sun_path, "server_socket");
len = sizeof (address);
/*向服务器发送连接请求*/
result = connect (sockfd, (struct sockaddr *)&address, len);
if (result == -1) {
printf ("ensure the server is up
");
perror ("connect");
exit (EXIT_FAILURE);
}
for (i = 0, ch_send = 'A'; i < 5; i++, ch_send++) {
if ((bytes = write(sockfd, &ch_send, 1)) == -1) { /*发消息给服务器*/
perror ("write");
exit (EXIT_FAILURE);
}
sleep (2); /*休息二秒钟再发一次*/
if ((bytes = read (sockfd, &ch_recv, 1)) == -1) { /*接收消息*/
perror ("read");
exit (EXIT_FAILURE);
}
printf ("receive from server data is %c
", ch_recv);
}
close (sockfd);
return (0);
}
程序说明：
先运行服务器端，然后再运行客户端可以在两边同时看到输出。服务器端先运行后会出现如下提示：
./sock_local_server Server is waiting for client connect...
这表示，服务器端已经被阻塞到到 accept() 这里，服务器就在此等候客户端的连接。
如果不是先运行服务器端，而直接运行客户端，那么客户端会提示：
./sock_local_client ensure the server is up connect: Connection refused
提示服务器没有准备好，连接被拒绝，从而直接退出程序。
如果服务器和客户端依次运行，可以在两边看到输出：
服务器端：
./sock_local_server Server is waiting for client connect... The server is waiting for client data... The character receiver from client is A The character receiver from client is B The character receiver from client is C The character receiver from client is D The character receiver from client is E
客户端：
./sock_local_client receive from server data is 1 receive from server data is 2 receive from server data is 3 receive from server data is 4 receive from server data is 5