1、網絡的Socket數據傳輸是壹種特殊的I/O，Socket也是壹種文件描述符。Socket也具有壹個類似於打開文件的函數調用Socket()，該函數返回壹個整型的Socket描述符，隨後的連接建立、數據傳輸等操作都是通過該Socket實現的。
2、下面用Socket實現壹個windows下的c語言socket通信例子，這裏客戶端傳遞壹個字符串，服務器端進行接收。
服務器端
#include "stdafx.h"
#include <stdio.h>
#include <winsock2.h>
#include <winsock2.h>
#define SERVER_PORT 5208 //偵聽端口
void main()
{
WORD wVersionRequested;
WSADATA wsaData;
int ret, nLeft, length;
SOCKET sListen, sServer; //偵聽套接字，連接套接字
struct sockaddr_in saServer, saClient; //地址信息
char *ptr;//用於遍歷信息的指針
//WinSock初始化
wVersionRequested=MAKEWORD(2, 2); //希望使用的WinSock DLL 的版本
ret=WSAStartup(wVersionRequested, &wsaData);
if(ret!=0)
{
printf("WSAStartup() failed!\n");
return;
}
//創建Socket,使用TCP協議
sListen=socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (sListen == INVALID_SOCKET)
{
WSACleanup();
printf("socket() faild!\n");
return;
}
//構建本地地址信息
saServer.sin_family = AF_INET; //地址家族
saServer.sin_port = htons(SERVER_PORT); //註意轉化為網絡字節序
saServer.sin_addr.S_un.S_addr = htonl(INADDR_ANY); //使用INADDR_ANY 指示任意地址
//綁定
ret = bind(sListen, (struct sockaddr *)&saServer, sizeof(saServer));
if (ret == SOCKET_ERROR)
{
printf("bind() faild! code:%d\n", WSAGetLastError());
closesocket(sListen); //關閉套接字
WSACleanup();
return;
}
//偵聽連接請求
ret = listen(sListen, 5);
if (ret == SOCKET_ERROR)
{
printf("listen() faild! code:%d\n", WSAGetLastError());
closesocket(sListen); //關閉套接字
return;
}
printf("Waiting for client connecting!\n");
printf("Tips: Ctrl+c to quit!\n");
//阻塞等待接受客戶端連接
while(1)//循環監聽客戶端，永遠不停止，所以，在本項目中，我們沒有心跳包。
{
length = sizeof(saClient);
sServer = accept(sListen, (struct sockaddr *)&saClient, &length);
if (sServer == INVALID_SOCKET)
{
printf("accept() faild! code:%d\n", WSAGetLastError());
closesocket(sListen); //關閉套接字
WSACleanup();
return;
}
char receiveMessage[5000];
nLeft = sizeof(receiveMessage);
ptr = (char *)&receiveMessage;
while(nLeft>0)
{
//接收數據
ret = recv()(sServer, ptr, 5000, 0);
if (ret == SOCKET_ERROR)
{
printf("recv() failed!\n");
return;
}
if (ret == 0) //客戶端已經關閉連接
{
printf("Client has closed the connection\n");
break;
}
nLeft -= ret;
ptr += ret;
}
printf("receive message:%s\n", receiveMessage);//打印我們接收到的消息。
}
// closesocket(sListen);
// closesocket(sServer);
// WSACleanup();
}
客戶端
#include "stdafx.h"
#include <stdio.h>
#include <stdlib.h>
#include <winsock2.h>
#define SERVER_PORT 5208 //偵聽端口
void main()
{
WORD wVersionRequested;
WSADATA wsaData;
int ret;
SOCKET sClient; //連接套接字
struct sockaddr_in saServer; //地址信息
char *ptr;
BOOL fSuccess = TRUE;
//WinSock初始化
wVersionRequested = MAKEWORD(2, 2); //希望使用的WinSock DLL的版本
ret = WSAStartup(wVersionRequested, &wsaData);
if(ret!=0)
{
printf("WSAStartup() failed!\n");
return;
}
//確認WinSock DLL支持版本2.2
if(LOBYTE(wsaData.wVersion)!=2 || HIBYTE(wsaData.wVersion)!=2)
{
WSACleanup();
printf("Invalid WinSock version!\n");
return;
}
//創建Socket,使用TCP協議
sClient = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (sClient == INVALID_SOCKET)
{
WSACleanup();
printf("socket() failed!\n");
return;
}
//構建服務器地址信息
saServer.sin_family = AF_INET; //地址家族
saServer.sin_port = htons(SERVER_PORT); //註意轉化為網絡節序
saServer.sin_addr.S_un.S_addr = inet_addr("192.168.1.127");
//連接服務器
ret = connect(sClient, (struct sockaddr *)&saServer, sizeof(saServer));
if (ret == SOCKET_ERROR)
{
printf("connect() failed!\n");
closesocket(sClient); //關閉套接字
WSACleanup();
return;
}
char sendMessage[]="hello this is client message!";
ret = send (sClient, (char *)&sendMessage, sizeof(sendMessage), 0);
if (ret == SOCKET_ERROR)
{
printf("send() failed!\n");
}
else
printf("client info has been sent!");
closesocket(sClient); //關閉套接字
WSACleanup();
}