Cfsocket communication on iOS

Client: Import header file:
# Import <sys/socket. h>
# Import <netinet/in. h>
# Import <ARPA/inet. h>
# Import <unistd. h>

1. Create a connection
Cfsocketcontext sockcontext = {0, // the version of the struct, which must be 0
Self,// Data of any pointer, which can be used when the cfsocket object is created. This pointer is passed to all callback defined in the context.
 Null, // A retain callback defined in the pointer above. It can be null.
 Null, null };

Cfsocketref _ socket = (kcfallocatordefault, // allocate memory for the new object, which can be nil
 Pf_inet, // protocol family. If it is 0 or negative, the default value is pf_inet.
 Sock_stream, // socket type. If the protocol family is pf_inet, It defaults to sock_stream.
 Ipproto_tcp, // SOCKET protocol. If the protocol family is pf_inet and the Protocol is 0 or negative, ipproto_tcp is used by default.
 Kcfsocketconnectcallback, // Specifies the socket message type that triggers the callback function. For details, see callback types.
 Tcpserverconnectcallback, // The callback function triggered in the preceding case
 & Sockcontext // an object holding cfsocket structure information, which can be nil
 );

If (_ socket! = Nil ){
   Struct sockaddr_in addr4; // IPv4
   Memset (& addr4, 0, sizeof (addr4 ));
   Addr4.sin _ Len = sizeof (addr4 );
   Addr4.sin _ family = af_inet;
   Addr4.sin _ Port = htons (8888 );
   Addr4.sin _ ADDR. s_addr = inet_addr ([straddress utf8string]);// Convert the string address to a machine-recognized network address
   
   // Convert the address in the sockaddr_in struct to data
   Cfdataref address = cfdatacreate (kcfallocatordefault, (uint8 *) & addr4, sizeof (addr4 ));
   Cfsocketconnecttoaddress(_ Socket, // connected socket
 Address, // cfdataref type object that contains the remote address of the above socket
 -1// Connection timeout. If the value is negative, the connection is not attempted. Instead, the connection is placed in the background. If the _ socket message type is kcfsocketconnectcallbackWill trigger the callback function in the background when the connection is successful or fails.
 );

 Cfrunloopref crunref = cfrunloopgetcurrent ();// Obtain the loop of the current thread
   // Create a loop, but it is not actually added to the loop. You need to call cfrunloopaddsource
   Cfrunloopsourceref sourceref = cfsocketcreaterunloopsouRCE (kcfallocatordefault, _ socket, 0 );
   Cfrunloopaddsource (crunref, // running cycle
   Sourceref,// Added running cycle source, which will be retaken once
 Kcfrunloopcommonmodes// Added running cycle source Mode
   );
   Cfrelease (courceref );
}

2. Set the callback function
// Format of the socket callback function:
Static void tcpserverconnectcallback(Cfsocketref socket, cfsocketcallbacktype type, cfdataref address, const void * data, void * info ){
   If (Data! = NULL ){
       // When the socket is kcfsocketconnectcallbackIf the callback fails, an error code pointer is returned. Otherwise, null is returned.
       Nslog (@ "connection failed ");
       Return;
   }
   Tcpclient * client = (tcpclient *) Info;
   // Read the received data
   [Info performslectorinbackgrouNd: @ selector (readstream) withobject: Nil];
}

3. receive and send data
// Read the received data
-(Void) readstream {
   Char buffer [1024];
   NSAID utoreleasepool * Pool = [[NSAID utoreleasepool alloc] init];
   While (Recv (cfsocketgetnative (_ socket), // If the socket associated with the local machine has expired, return-1: invalid_socket
          Buffer, sizeof (buffer), 0 )){
       Nslog (@ "% @", [nsstring stringwithuf8string: Buffer]);
   }
}

// Send data
-(Void) sendmessage {
   Nsstring * stringtosend = @ "hello ";
   Char * Data = [stringtosend utf8string];
   Send (sfsocketgetnative (_ socket), data, strlen (data) + 1, 0 );
}

Server:

Cfsockteref _ socket;
Cfwritestreamref outputstream = NULL;

Int setupsocket (){
   _ Socket = cfsocketcreate (kcfallocatordefault, pf_inet, sock_stream, ipproto_tcp, kcfsocketacceptcallback, tcpserveracceptcallback, null );
   If (null ==_socket ){
     Nslog (@ "cannot create socket! ");
     Return 0;
   }
   
   Int optval = 1;
   Setsockopt (cfsocketgetnative (_ socket), sol_socket, so_reuseaddr, // allow reuse of local addresses and ports
(Void *) & optval, sizeof (optval ));
   
   Struct sockaddr_in addr4;
   Memset (& addr4, 0, sizeof (addr4 ));
   Addr4.sin _ Len = sizeof (addr4 );
   Addr4.sin _ family = af_inet;
   Addr4.sin _ Port = htons (port );
   Addr4.sin _ ADDR. s_addr = htonl (inaddr_any );
   Cfdataref address = cfdatacreate (kcfallocatordefault, (uint8 *) & addr4, sizeof (addr4 ));
   
   If (kcfsocketsuccess! = Cfsocketsetaddress (_ socket, address )){
     Nslog (@ "bind to address failed! ");
     If (_ socket)
            Cfrelease (_ socket );
     _ Socket = NULL;