使用SOCKET TCP

　　刚刚接触SOCKET编程，网上看了一些资料，发现做些简单的应用还是不难。但是要深入了解SOCKET编程还需要系统的看一些书。一般在进程间通信TCP是一种不错的方式。 ---XXX

TCP链接是面向流的链接，因此数据在应用程序看来应该是没有边界的，之前对send和recv函数中发送的大小和返回值没有理解，今天做了一个实验有了进一步的了解。socket一些常用的函数介绍可以在这里找到http://blog.csdn.net/ithzhang/article/details/8448655

之前有个疑问是如果一方向另一方一次发送大量的数据，超过了TCP缓冲区的大小，那么接收方该如何处理。这里就要用到recv函数的返回值了，它指示了本次调用函数实际接收的字节数，如果这个值小于我们需要接收的数据，那么就需要再一次调用recv函数。

下面是我测试的代码，代码是在VS2013下编译的。

欢迎一起讨论，指正错误。

服务器端：

 #include <winsock2.h>
 #include <iostream>
 #include <numeric>
 #include <vector>
 #include <algorithm>
 #pragma comment(lib,"ws2_32.lib")

 using namespace std;

 const int port = ;

 int main(int argc,char**argv)
 {
     WSADATA ws;
     if (WSAStartup(MAKEWORD(, ), &ws) != )
     {
         cout << "init windows socket failed::" << GetLastError() << endl;
         return -;
     }

     SOCKET serverSocket;

     serverSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);

     sockaddr_in serverAddr;
     serverAddr.sin_family = AF_INET;
     serverAddr.sin_port = htons(port);
     //serverAddr.sin_addr.s_addr = inet_addr("192.168.182.1");
     serverAddr.sin_addr.s_addr = htonl(INADDR_ANY);
     memset(&(serverAddr.sin_zero), , sizeof(serverAddr.sin_zero));

     if (bind(serverSocket,  (SOCKADDR*)&serverAddr, sizeof(serverAddr))!=)
     {
         cout << "bind server socket failed\n";
         WSACleanup();
         return -;
     }

     if (listen(serverSocket,)!=)
     {
         cout << "listen failded\n";
         return -;
     }

     const int buf_size =  * ;

     float *buf = new float[buf_size];    

     for_each(buf, buf + buf_size, [](float &v){v = ; });
     cout << std::accumulate(buf, buf + buf_size, ) << endl;
     while (true)
     {
         int add_size = sizeof(SOCKADDR);

         sockaddr_in client_addr;
         SOCKET accept_sock = accept(serverSocket, (SOCKADDR*)&client_addr, &add_size);
         if (accept_sock == -)
         {
             cout << "accept faild\n";
             continue;
         }

         int send_size = send(accept_sock, (char*)buf, buf_size*sizeof(float), );
         cout << send_size << endl;
         if (send_size==-)
         {
             cout << "send data faild\n";
             continue;
         }

     }

     delete[] buf;
     return ;
 }

客户端的：

 #include <iostream>
 #include <numeric>
 #include <winsock2.h>
 #include <algorithm>

 #pragma comment(lib,"ws2_32.lib")
 using namespace std;
 const int port = ;
 int main()
 {
     WSADATA ws;

     if (WSAStartup(MAKEWORD(, ), &ws) != )
     {
         cout << "load socket faild\n";
         WSACleanup();
         return -;
     }

     SOCKET client_sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);

     sockaddr_in server_addr;
     server_addr.sin_family = AF_INET;
     server_addr.sin_port = htons(port);
     server_addr.sin_addr.s_addr = inet_addr("192.168.182.1");
     memset(&(server_addr.sin_zero), , sizeof(server_addr.sin_zero));

     if (connect(client_sock, (SOCKADDR*)&server_addr, sizeof(SOCKADDR)) != )
     {
         cout << "connect to server failed \n";
         WSACleanup();
         return -;
     }
     const int buf_size =  * ;

     float *buf = new float[buf_size] ;
     for_each(buf, buf + buf_size, [](float &v){v = ; });
     cout << std::accumulate(buf, buf + buf_size, ) << endl;

     int recved_size = ;

     do
     {
         int rsz = recv(client_sock, (char*)buf + recved_size, buf_size*sizeof(float)-recved_size, );
         if (rsz == -)
         {
             cout << "recv data failed\n";
             WSACleanup();
         }
         recved_size += rsz;

     } while (recved_size<buf_size*sizeof(float));

     cout << std::accumulate(buf, buf + buf_size, ) << endl;
     delete[] buf;

     closesocket(client_sock);
 }