• <ins id="pjuwb"></ins>
    <blockquote id="pjuwb"><pre id="pjuwb"></pre></blockquote>
    <noscript id="pjuwb"></noscript>
          <sup id="pjuwb"><pre id="pjuwb"></pre></sup>
            <dd id="pjuwb"></dd>
            <abbr id="pjuwb"></abbr>

            牽著老婆滿街逛

            嚴以律己,寬以待人. 三思而后行.
            GMail/GTalk: yanglinbo#google.com;
            MSN/Email: tx7do#yahoo.com.cn;
            QQ: 3 0 3 3 9 6 9 2 0 .

            Beginning Winsock Programming - Simple TCP server

            Introduction

            The WinSock (Windows Sockets) API is a socket programming library for Microsoft Windows Operating Systems. It was originally based on Berkeley sockets. But several Microsoft specific changes were employed. In this article I shall attempt to introduce you to socket programming using WinSock, assuming that you have never done any kind of network programming on any Operating System.

            If you only have a single machine, then don't worry. You can still program WinSock. You can use the local loop-back address called localhost with the IP address 127.0.0.1. Thus if you have a TCP server running on your machine, a client program running on the same machine can connect to the server using this loop-back address.

            Simple TCP Server

            In this article I introduce you to WinSock through a simple TCP server, which we shall create step by step. But before we begin, there are a few things that you must do, so that we are truly ready for starting our WinSock program

            • Initially use the VC++ 6.0 App Wizard to create a Win32 console application.?
            • Remember to set the option to add support for MFC
            • Open the file stdafx.h and add the following line :- #include <winsock2.h>
            • Also #includeconio.h and iostream just after winsock2.h
            • Take Project-Settings-Link and add ws2_32.lib to the library modules list.

            The main function

            				int _tmain(int argc, TCHAR* argv[], TCHAR* envp[])
            {
                int nRetCode = 0;	
            	
                cout << "Press ESCAPE to terminate program\r\n";
                AfxBeginThread(ServerThread,0);
                while(_getch()!=27);
            	
                return nRetCode;
            }

            What we do in our main() is to start a thread and then loop a call to _getch(). _getch() simply waits till a key is pressed and returns the ASCII value of the character read. We loop till a value of 27 is returned, since 27 is the ASCII code for the ESCAPE key. You might be wondering that even if we press ESCAPE, the thread we started would still be active. Don't worry about that at all. When main() returns the process will terminate and the threads started by our main thread will also be abruptly terminated.

            The ServerThread function

            What I will do now is to list our ServerThread function and use code comments to explain what each relevant line of code does. Basically what our TCP server does is this. It listens on port 20248, which also happens to be my Code Project membership ID. Talk about coincidences. When a client connects, the server will send back a message to the client giving it's IP address and then close the connection and go back to accepting connections on port 20248. It will also print a line on the console where it's running that there was a connection from this particular IP address. All in all, an absolutely useless program, you might be thinking. In fact some of you might even think this is as useless as SNDREC32.EXE which comes with Windows. Cruel of those people I say.

            UINT  ServerThread(LPVOID pParam)
            {	
                cout << "Starting up TCP server\r\n";
            
                //A SOCKET is simply a typedef for an unsigned int.//In Unix, socket handles were just about same as file //handles which were again unsigned ints.//Since this cannot be entirely true under Windows//a new data type called SOCKET was defined.
                SOCKET server;
            
                //WSADATA is a struct that is filled up by the call //to WSAStartup
                WSADATA wsaData;
            
                //The sockaddr_in specifies the address of the socket//for TCP/IP sockets. Other protocols use similar structures.
                sockaddr_in local;
            
                //WSAStartup initializes the program for calling WinSock.//The first parameter specifies the highest version of the //WinSock specification, the program is allowed to use.int wsaret=WSAStartup(0x101,&wsaData);
            
                //WSAStartup returns zero on success.//If it fails we exit.if(wsaret!=0)
                {
                    return0;
                }
            
                //Now we populate the sockaddr_in structure
                local.sin_family=AF_INET; //Address family
                local.sin_addr.s_addr=INADDR_ANY; //Wild card IP address
                local.sin_port=htons((u_short)20248); //port to use//the socket function creates our SOCKET
                server=socket(AF_INET,SOCK_STREAM,0);
            
                //If the socket() function fails we exitif(server==INVALID_SOCKET)
                {
                    return0;
                }
            
                //bind links the socket we just created with the sockaddr_in //structure. Basically it connects the socket with //the local address and a specified port.//If it returns non-zero quit, as this indicates errorif(bind(server,(sockaddr*)&local,sizeof(local))!=0)
                {
                    return0;
                }
            
                //listen instructs the socket to listen for incoming //connections from clients. The second arg is the backlogif(listen(server,10)!=0)
                {
                    return0;
                }
            
                //we will need variables to hold the client socket.//thus we declare them here.
                SOCKET client;
                sockaddr_in from;
                int fromlen=sizeof(from);
            
                while(true)//we are looping endlessly
                {
                    char temp[512];
            
                    //accept() will accept an incoming//client connection
                    client=accept(server,
                        (struct sockaddr*)&from,&fromlen);
            		
                    sprintf(temp,"Your IP is %s\r\n",inet_ntoa(from.sin_addr));
            
                    //we simply send this string to the client
                    send(client,temp,strlen(temp),0);
                    cout << "Connection from " << inet_ntoa(from.sin_addr) <<"\r\n";
            		
                    //close the client socket
                    closesocket(client);
            
                }
            
                //closesocket() closes the socket and releases the socket descriptor
                closesocket(server);
            
                //originally this function probably had some use//currently this is just for backward compatibility//but it is safer to call it as I still believe some//implementations use this to terminate use of WS2_32.DLL 
                WSACleanup();
            
                return0;
            }

            Testing it out

            Run the server and use telnet to connect to port 20248 of the machine where the server is running. If you have it on the same machine connect to localhost.

            Sample Output

            We see this output on the server

            E:\work\Server\Debug>server
            Press ESCAPE to terminate program
            Starting up TCP server
            Connection from 203.200.100.122
            Connection from 127.0.0.1
            E:\work\Server\Debug>

            And this is what the client gets

            nish@sumida:~$ telnet 202.89.211.88 20248
            Trying 202.89.211.88...
            Connected to 202.89.211.88.
            Escape character is '^]'.
            Your IP is 203.200.100.122
            Connection closed by foreign host.
            nish@sumida:~$

            Conclusion

            Well, in this article you learned how to create a simple TCP server. In further articles I'll show you more stuff you can do with WinSock including creating a proper TCP client among other things. If anyone has problems with compiling the code, mail me and I shall send you a zipped project. Thank you.

            About Nishant Sivakumar



            Editor
            Site Builder
            Nish is a real nice guy living in Toronto who has been coding since 1990, when he was 13 years old. Originally from sunny Trivandrum in India, he has moved to Toronto so he can enjoy the cold winter and get to play in some snow.

            He works for The Code Project and is in charge of the MFC libraries Ultimate Toolbox, Ultimate Grid and Ultimate TCP/IP that are sold exclusively through The Code Project Storefront. He frequents the CP discussion forums when he is not coding, reading or writing. Nish hopes to visit at least three dozen countries before his human biological mechanism stops working (euphemism used to avoid the use of the d-word here). Oh btw, it must be mentioned that normally Nish is not inclined to speak about himself in the 3rd person.

            Nish has been a Microsoft Visual C++ MVP since October, 2002 - awfully nice of Microsoft, he thinks. He maintains an MVP tips and tricks web site - www.voidnish.com where you can find a consolidated list of his articles, writings and ideas on VC++, MFC, .NET and C++/CLI. Oh, and you might want to check out his blog on C++/CLI, MFC, .NET and a lot of other stuff - blog.voidnish.com

            Nish loves reading Science Fiction, P G Wodehouse and Agatha Christie, and also fancies himself to be a decent writer of sorts. He has authored a romantic comedy Summer Love and Some more Cricket as well as a programming book – Extending MFC applications with the .NET Framework.

            posted on 2006-04-18 17:41 楊粼波 閱讀(636) 評論(0)  編輯 收藏 引用 所屬分類: 文章收藏

            久久久久无码中| 久久狠狠色狠狠色综合| 国内精品久久久久久久涩爱 | 无码8090精品久久一区| 99精品久久久久久久婷婷| 国产成人久久久精品二区三区| 精品国产乱码久久久久久呢| 精品无码人妻久久久久久| 亚洲国产成人久久综合区| 国产激情久久久久影院小草 | 国产午夜福利精品久久| 亚洲精品国产自在久久| 久久精品99久久香蕉国产色戒| 久久久SS麻豆欧美国产日韩| 久久精品毛片免费观看| 色综合久久天天综线观看| 99久久精品国产高清一区二区| 久久综合亚洲欧美成人| 99精品国产免费久久久久久下载| 久久精品无码一区二区日韩AV | 亚洲七七久久精品中文国产| 精品久久久久久久无码 | 热久久最新网站获取| 日韩电影久久久被窝网| 欧美亚洲另类久久综合| 国产精品久久久福利| 午夜天堂精品久久久久| 97久久久久人妻精品专区| 偷偷做久久久久网站| 天天综合久久一二三区| 久久久久久A亚洲欧洲AV冫 | 色妞色综合久久夜夜| 久久精品卫校国产小美女| 久久影院亚洲一区| 影音先锋女人AV鲁色资源网久久| 性做久久久久久免费观看| 久久国产精品免费| 亚洲精品国产综合久久一线| 久久午夜无码鲁丝片午夜精品| 久久久久一本毛久久久| 久久免费99精品国产自在现线 |