使用SOCKET TCP

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　　剛剛接觸SOCKET編程，網上看了一些資料，發現做些簡單的應用還是不難。但是要深入瞭解SOCKET編程還需要系統的看一些書。一般在處理序間通訊TCP是一種不錯的方式。 ---XXX

TCP連結是面向流的連結，因此資料在應用程式看來應該是沒有邊界的，之前對send和recv函數中發送的大小和傳回值沒有理解，今天做了一個實驗有了進一步的瞭解。socket一些常用的函數介紹可以在這裡找到http://blog.csdn.net/ithzhang/article/details/8448655 

之前有個疑問是如果一方向另一方一次發送大量的資料，超過了TCP緩衝區的大小，那麼接收方該如何處理。這裡就要用到recv函數的傳回值了，它指示了本次調用函數實際接收的位元組數，如果這個值小於我們需要接收的資料，那麼就需要再一次調用recv函數。

 

下面是我測試的代碼，代碼是在VS2013下編譯的。

歡迎一起討論，指正錯誤。

伺服器端：

 1 #include <winsock2.h> 2 #include <iostream> 3 #include <numeric> 4 #include <vector> 5 #include <algorithm> 6 #pragma comment(lib,"ws2_32.lib") 7  8  9 using namespace std;10 11 const int port = 2048;12 13 int main(int argc,char**argv)14 {15     WSADATA ws;16     if (WSAStartup(MAKEWORD(2, 2), &ws) != 0)17     {18         cout << "init windows socket failed::" << GetLastError() << endl;19         return -1;20     }21 22     SOCKET serverSocket;23 24     serverSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);25 26     sockaddr_in serverAddr;27     serverAddr.sin_family = AF_INET;28     serverAddr.sin_port = htons(port);29     //serverAddr.sin_addr.s_addr = inet_addr("192.168.182.1");30     serverAddr.sin_addr.s_addr = htonl(INADDR_ANY);31     memset(&(serverAddr.sin_zero), 0, sizeof(serverAddr.sin_zero));32     33     if (bind(serverSocket,  (SOCKADDR*)&serverAddr, sizeof(serverAddr))!=0)34     {35         cout << "bind server socket failed\n";36         WSACleanup();37         return -1;38     }39 40     if (listen(serverSocket,10)!=0)41     {42         cout << "listen failded\n";43         return -1;44     }45 46     const int buf_size = 1024 * 1024;47     48     float *buf = new float[buf_size];    49     50     for_each(buf, buf + buf_size, [](float &v){v = 1; });51     cout << std::accumulate(buf, buf + buf_size, 0) << endl;52     while (true)53     {54         int add_size = sizeof(SOCKADDR);55 56         sockaddr_in client_addr;57         SOCKET accept_sock = accept(serverSocket, (SOCKADDR*)&client_addr, &add_size);58         if (accept_sock == -1)59         {60             cout << "accept faild\n";61             continue;62         }63 64         int send_size = send(accept_sock, (char*)buf, buf_size*sizeof(float), 0);65         cout << send_size << endl;66         if (send_size==-1)67         {68             cout << "send data faild\n";69             continue;70         }71 72     }73 74     delete[] buf;75     return 0;76 }

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用戶端的：

 1 #include <iostream> 2 #include <numeric> 3 #include <winsock2.h> 4 #include <algorithm> 5  6 #pragma comment(lib,"ws2_32.lib") 7 using namespace std; 8 const int port = 2048; 9 int main()10 {11     WSADATA ws;12 13     if (WSAStartup(MAKEWORD(2, 2), &ws) != 0)14     {15         cout << "load socket faild\n";16         WSACleanup();17         return -1;18     }19 20     SOCKET client_sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);21 22     sockaddr_in server_addr;23     server_addr.sin_family = AF_INET;24     server_addr.sin_port = htons(port);25     server_addr.sin_addr.s_addr = inet_addr("192.168.182.1");26     memset(&(server_addr.sin_zero), 0, sizeof(server_addr.sin_zero));27 28     if (connect(client_sock, (SOCKADDR*)&server_addr, sizeof(SOCKADDR)) != 0)29     {30         cout << "connect to server failed \n";31         WSACleanup();32         return -1;33     }34     const int buf_size = 1024 * 1024;35     36     float *buf = new float[buf_size] ;37     for_each(buf, buf + buf_size, [](float &v){v = 0; });38     cout << std::accumulate(buf, buf + buf_size, 0) << endl;39 40     int recved_size = 0;41     42     do 43     {44         int rsz = recv(client_sock, (char*)buf + recved_size, buf_size*sizeof(float)-recved_size, 0);45         if (rsz == -1)46         {47             cout << "recv data failed\n";48             WSACleanup();49         }50         recved_size += rsz;51         52     } while (recved_size<buf_size*sizeof(float));53         54     cout << std::accumulate(buf, buf + buf_size, 0) << endl;55     delete[] buf;56 57 58     closesocket(client_sock);59 }

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使用SOCKET TCP