Linux socket programming

Linux socket programming is urgent-Linux general technology-Linux technology and application information. The following is a detailed description. // This is network socket programming
// This is the server side
# Include
# Include
# Include
# Include
# Include
# Include
# Define oops (ch) {perror (ch); return 0 ;}

Int main ()
{Int server_sockfd, client_sockfd;
Int server_len, client_len;
Struct sockaddr_un server_address;
Struct sockaddr_un client_address;

Unlink ("/tmp/server_socket ");

If (server_sockfd = socket (PF_UNIX, SOCK_STREAM, 0) =-1)
Oops ("socket ")

Server_address.sun_family = AF_UNIX;
Strcpy (server_address.sun_path, "/tmp/server_socket ");
Server_len = sizeof (server_address );

If (bind (server_sockfd, (struct sockaddr *) & server_address, server_len) =-1)
Oops ("bind ");

If (listen (server_sockfd, 4) =-1)
Oops ("listen ");

While (1)
{
Char ch;
Printf ("server waiting... \ n ");

If (client_sockfd = accept (server_sockfd, (struct sockaddr *) & client_address, & client_len) =-1)
Oops ("accept ");

Read (client_sockfd, & ch, 1 );

Ch ++;
Write (client_sockfd, & ch, 1 );
}
Return 0;

Close (client_sockfd );

}

// This is the client
# Include
# Include
# Include
# Include
# Include
# Include
# Define oops (ch) {perror (ch); return 0 ;}

Int main ()
{Int sockfd;
Int len;
Char ch = 'a ';
Struct sockaddr_un address;
If (sockfd = socket (PF_UNIX, SOCK_STREAM, 0) =-1)
Oops ("socket ");

Address. sun_family = AF_UNIX;
If (strncpy (address. sun_path, "/tmp/server_socket", 18) =-1)
Oops ("strcpy ");
Len = sizeof (address );

// If (bind (sockfd, address, len) =-1)
// Oops ("bind ");

If (connect (sockfd, (struct sockaddr *) & address, len) =-1)
Oops ("connect ");

If (write (sockfd, & ch, 1) =-1) // The program seems to be blocked here. Why !?
Oops ("write ");
Sleep (2 );
Read (sockfd, & ch, 1 );
Printf ("char from server = % c \ n", ch );
Close (sockfd );
Return 0;

}

I don't understand how to run the client after running the server.
Why does the program block write when running the client ??
Urgent!
Thank you!