DEMO code of the select model on a single server and multiple clients

# Include <stdio. h>
# Include <iostream>
# Include <winsock2.h>
Using namespace STD;
Int main (){
Word version = makeword (2, 2 );
Wsadata;
Socket listensocket;
Socket acceptsocket;
Socket clientsocket [fd_setsize];
Int static Index = 0;
DWORD block = 1l;
Fd_set readset;
// Load the socket Library

Int F = wsastartup (version, & wsadata );
If (F! = 0 ){
Cout <"An error occurred while loading the Winsock database! Error Code: "<wsagetlasterror () <Endl;
Return-1;

}

// Create a listener socket

Listensocket = socket (af_inet, sock_stream, ipproto_ip );
If (listensocket = invalid_socket ){
Wsacleanup ();
Cout <"failed to create the listening socket! Error Code: "<wsagetlasterror () <Endl;
Return-1;

}
Cout <"listening socket created successfully! \ N "<Endl;

// Construct the server address

Sockaddr_in serverip;

Serverip. sin_family = af_inet;
Serverip. sin_port = htons (8108 );
Serverip. sin_addr.s_un.s_addr = htonl (inaddr_any );
If (BIND (listensocket, (sockaddr *) & serverip, sizeof (sockaddr) = socket_error ){
Cout <"server binding error! Error Code: "<wsagetlasterror () <Endl;
Return-1;

 

}

Cout <"binding successful! \ N "<Endl;
If (Listen (listensocket, 10) = socket_error ){
Cout <"error in listening mode! Error Code: "<wsagetlasterror () <Endl;
Return-1;
}
Cout <"the server has entered the listening mode! \ N "<Endl;

If (ioctlsocket (listensocket, fionbio, & Block) = socket_error ){
Cout <"the error message returned when the listener socket is set to non-blocking mode! Error Code: "<wsagetlasterror () <Endl;

Return-1;

}

Cout <"the listener socket has been set to non-blocking mode! \ N "<Endl;

// Accept client connection in non-blocking mode

While (true ){

Cout <"continues to accept client connection requests in non-blocking mode! \ N "<Endl;
// Clear the read set to 0

Fd_zero (& readset );

// Place the existing client connection to the collection!

For (INT I = 0; I <index; I ){

Cout <"put clientsocket [" <I <"] into the readset collection! \ N "<Endl;

Fd_set (clientsocket [I], & readset );
}
Cout <"listening socket into readset collection! \ N "<Endl;

Fd_set (listensocket, & readset );
If (select (0, & readset, null) = socket_error

Cout <"socet error of select listening! Error Code: "<wsagetlasterror () <Endl;
System ("pause ");
Return-1;
}

Cout <"if the SELECT statement is returned, the existing client is connected, the client data is read, or the client connection is disconnected! \ N "<Endl;

If (fd_isset (listensocket, & readset )){

Cout <"the current readset stores the listening socket! \ N "<Endl;
Acceptsocket = accept (listensocket, null, null );
If (acceptsocket! = Invalid_socket ){
Cout <"the client established a connection and saved it to clientsocket [" <index <! \ N "<Endl;
Clientsocket [Index] = acceptsocket;
Index ++;

} Else {
Cout <"client connection error received! Error Code: "<wsagetlasterror () <Endl;

Continue;

}
}

For (Int J = 0; j <index; j ){

If (fd_isset (clientsocket [J], & readset )){
Cout <"the current readset set contains client socket clientsocket [" <j <"] readable data! \ N [Message]"

Char buffer [100]; memset (buffer, 0,100 );

If (Recv (clientsocket [J], buffer, 100,0 )! = Socket_error ){

Cout <buffer <"[/messsage] \ n" <Endl;

} Else {

Cout <"client clientsocket [" <j <"] error! Error Code: "<wsagetlasterror () <Endl;
Clientsocket [J] = NULL;

Index --;
Closesocket (clientsocket [J])
Break;

}

}}
}
}

 

 

The code below is basically the same as the while (true) section described above, but I personally feel that the following method is better.

While (true)
{

Fd_set fdread = fdsocket;
If (: Select (0, & fdsocket, null) = socket_error)
{
Continue;
}
Else
{
Trace ("Wait somebody % I \ n", fdsocket. fd_count );
For (INT I = 0; I <(INT) fdsocket. fd_count; I ++)
{

If (fd_isset (fdsocket. fd_array [I], & fdsocket ))
{
If (fdsocket. fd_array [I] = slisten)
{
Cstring strip;
Sockaddr_in addrremote;
Int naddrlen = sizeof (addrremote );
Socket snew =: accept (slisten, (sockaddr *) & addrremote, & naddrlen );
Fd_set (snew, & fdsocket );
Strip. Format ("% s", inet_ntoa (addrremote. sin_addr ));
Trace ("new come % s \ n", strip );

} // End if = slisten
Else
{
Int nrecev =: Recv (fdsocket. fd_array [I], (char *) & recvpacket, sizeof (recvpacket), 0 );
If (nrecev> 0)
{
Trace ("Recv MSG % s \ n", recvpacket );

} Else
{
: Closesocket (fdsocket. fd_array [I]);
Fd_clr (fdsocket. fd_array [I], & fdsocket );
}
}
}

}
}
}
Return 0;