Server programming example

Int fd_set_nonblock (int fd)

{

Int RV;

Rv = fcntl (FD, f_getfl, 0 );

If (RV <0 ){

Printf ("fcntl error \ n ");

Return-1;

}

Rv = fcntl (FD, f_setfl, RV | o_nonblock );

If (RV <0 ){

Printf ("fcntl error \ n ");

Return-1;

}

Return 0;

}

Int init_server_socket ()

{

Int FD;

Struct sockaddr_in ADDR;

Int ret;

Int v_on = 1;

FD = socket (pf_inet, sock_stream, 0 );

If (FD <0 ){

Printf ("server socket create failed \ n ");

Return-1;

}

Ret = setsockopt (FD, sol_socket, so_reuseaddr, & v_on, sizeof (v_on ));

If (Ret! = 0 ){

Printf ("setsockopt error \ n ");

Goto out_close_socket;

}

Memset (& ADDR, 0, sizeof (struct sockaddr_in ));

ADDR. sin_family = af_inet;

ADDR. sin_addr.s_addr = inaddr_any;

ADDR. sin_port = htons (40000 );

Ret = BIND (FD, (struct sockaddr *) & ADDR, sizeof (ADDR ));

If (Ret <0 ){

Printf ("server socket BIND error \ n ");

Goto out_close_socket;

}

Ret = listen (FD, 20 );

If (Ret <0 ){

Printf ("server socket listen error \ n ");

Goto out_close_socket;

}

Ret = fd_set_nonblock (FD );

If (Ret! = 0 ){

Printf ("fd_set_nonblock () failed \ n ");

Goto out_close_socket;

}

Return FD;

Out_close_socket:

Close (FD );

Return-1;

}

Int main (INT argc, char * argv [])

{

Int listenfd;

Int RV;

Listenfd = init_server_socket ();

If (listenfd <0 ){

Exit (1 );

}

While (1 ){

Fd_set readfds;

Struct timeval T;

Int connfd;

Structsockaddr_in clientaddr;

Socklen_t addrlen;

Int R;

Fd_zero (& readfds );

If (listenfd> = 0) fd_set (listenfd, & readfds );

T. TV _sec = 60;

T. TV _usec = 0;

R = select (listenfd + 1, & readfds, null, null, & T );

If (r = 0 ){

Continue;

}

If (r <0 ){

If (errno! = Eintr)

Printf ("signal caught \ n ");

Continue;

}

If (! Fd_isset (listenfd, & readfds ))

Continue;

Memset (& clientaddr, 0, sizeof (struct sockaddr_in ));

Addrlen = sizeof (struct sockaddr_in );

Connfd = accept (listenfd, (struct sockaddr *) & clientaddr, & addrlen );

If (connfd <0 ){

Continue;

}

**********/

}

Close (listenfd );

Return 0;

}