程序說明：
程序裏包含服務端和客戶端兩個程序，它們之間使用 AF_UNIX 實現本機數據流通信。使用 AF_UNIX 域實際上是使用本地 socket 文件來通信。
服務器端代碼：
#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; /*聲明一個UNIX域套接字結構*/
struct sockaddr_un client_address;
int i, bytes;
char ch_send, ch_recv;
unlink ("server_socket"); /*刪除原有server_socket對象*/
/*創建 socket, 通信協議爲AF_UNIX, SCK_STREAM 數據方式*/
server_sockfd = socket (AF_UNIX, SOCK_STREAM, 0);
/*配置服務器信息(通信協議)*/
server_address.sun_family = AF_UNIX;
/*配置服務器信息(socket 對象)*/
strcpy (server_address.sun_path, "server_socket");
/*配置服務器信息(服務器地址長度)*/
server_len = sizeof (server_address);
/*綁定 socket 對象*/
bind (server_sockfd, (struct sockaddr *)&server_address, server_len);
/*監聽網絡,隊列數爲5*/
listen (server_sockfd, 5);
printf ("Server is waiting for client connect...\n");
client_len = sizeof (client_address);
/*接受客戶端請求; 第2個參數用來存儲客戶端地址; 第3個參數用來存儲客戶端地址的大小*/
/*建立(返回)一個到客戶端的文件描述符,用以對客戶端的讀寫操作*/
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...\n");
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\n", ch_recv);
sleep (1);
if ((bytes = write (client_sockfd, &ch_send, 1)) == -1) {
perror ("read");
exit (EXIT_FAILURE);
}
}
close (client_sockfd);
unlink ("server socket");
}
客戶端代碼：
#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;
/*創建socket,AF_UNIX通信協議,SOCK_STREAM數據方式*/
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);
/*向服務器發送連接請求*/
result = connect (sockfd, (struct sockaddr *)&address, len);
if (result == -1) {
printf ("ensure the server is up\n");
perror ("connect");
exit (EXIT_FAILURE);
}
for (i = 0, ch_send = 'A'; i < 5; i++, ch_send++) {
if ((bytes = write(sockfd, &ch_send, 1)) == -1) { /*發消息給服務器*/
perror ("write");
exit (EXIT_FAILURE);
}
sleep (2); /*休息二秒鐘再發一次*/
if ((bytes = read (sockfd, &ch_recv, 1)) == -1) { /*接收消息*/
perror ("read");
exit (EXIT_FAILURE);
}
printf ("receive from server data is %c\n", ch_recv);
}
close (sockfd);
return (0);
}
程序說明：
先運行服務器端，然後再運行客戶端可以在兩邊同時看到輸出。服務器端先運行後會出現如下提示：
./sock_local_server
Server is waiting for client connect...
這表示，服務器端已經被阻塞到到 accept() 這裏，服務器就在此等候客戶端的連接。
如果不是先運行服務器端，而直接運行客戶端，那麼客戶端會提示：
./
sock_local_client
ensure the server is up
connect: Connection refused
提示服務器沒有準備好，連接被拒絕，從而直接退出程序。
如果服務器和客戶端依次運行，可以在兩邊看到輸出：
服務器端：
./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
客戶端：
./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
