一个简单的Winsock例子

这个例子试图创建服务端/客户端结构，先建立服务端和客户端连接，并在客户端发送一些数据到服务端，然后结束连接

服务端程序

// Server
#ifndef WIN32_LEAN_AND_MEAN
#define WIN32_LEAN_AND_MEAN
#endif
#define DEFAULT_PORT "27015"
#define DEFAULT_BUFLEN 512
#include <WinSock2.h>
#include <WS2tcpip.h>
#include <IPHlpApi.h>
#include <stdio.h>
#pragma comment(lib, "WS2_32.lib")
int main(int argc, char ** argv)
{
	// 初始化 Winsock
	WSADATA wsaData;
	int iResult;
	iResult = WSAStartup(MAKEWORD(2,2),&wsaData);
	if(iResult != 0)
	{
		printf("WSAStartup failed: %d\n", iResult);
		return 1;
	}

	// 获取连接属性
	struct addrinfo * result = NULL, * ptr = NULL, hints;
	ZeroMemory(&hints, sizeof(hints));
	hints.ai_family = AF_INET;
	hints.ai_socktype = SOCK_STREAM;
	hints.ai_protocol = IPPROTO_TCP;
	hints.ai_flags = AI_PASSIVE;

	iResult = getaddrinfo(NULL, DEFAULT_PORT, &hints, &result);
	if (iResult != 0) {
		printf("getaddrinfo failed: %d\n", iResult);
		WSACleanup();
		return 1;
	}

	// 创建 Listen Socket 对象
	SOCKET ListenSocket = INVALID_SOCKET;
	ListenSocket = socket(result->ai_family, result->ai_socktype, result->ai_protocol);
	if (ListenSocket == INVALID_SOCKET) {
		printf("Error at socket(): %ld\n", WSAGetLastError());
		freeaddrinfo(result);
		WSACleanup();
		return 1;
	}

	// 绑定连接端口
	iResult = bind(ListenSocket, result->ai_addr, (int)result->ai_addrlen);
	if (iResult == SOCKET_ERROR) {
		printf("bind failed: %d\n", WSAGetLastError());
		freeaddrinfo(result);
		closesocket(ListenSocket);
		WSACleanup();
		return 1;
	}

	// 开始监听
	if (listen(ListenSocket, SOMAXCONN) == SOCKET_ERROR) {
		printf("Error at bind(): %ld\n", WSAGetLastError());
		closesocket(ListenSocket);
		WSACleanup();
		return 1;
	}

	// Accept 一个链接（阻塞）
	SOCKET ClientSocket = INVALID_SOCKET;
	ClientSocket = accept(ListenSocket, NULL, NULL);
	if (ClientSocket == INVALID_SOCKET) {
		printf("accept failed: %d\n", WSAGetLastError());
		closesocket(ListenSocket);
		WSACleanup();
		return 1;
	}

	// 接受一些数据
	char recvbuf[DEFAULT_BUFLEN+1];
	do {
		iResult = recv(ClientSocket, recvbuf, DEFAULT_BUFLEN, 0);
		if (iResult > 0) {
			// Echo the buffer to the console
			recvbuf[DEFAULT_BUFLEN] = 0;
			printf("Bytes received: %d, %s\n", iResult, recvbuf);
		}
		else if (iResult == 0) {
			printf("Connection closing ...\n");
		}
		else {
			printf("recv failed: %d\n", WSAGetLastError());
			closesocket(ClientSocket);
			WSACleanup();
			return 1;
		}
	} while (iResult > 0);

	// shutdown the send half of the connection since no more data will be sent
	iResult = shutdown(ClientSocket, SD_SEND);
	if (iResult == SOCKET_ERROR) {
		printf("shutdown failed: %d\n", WSAGetLastError());
		closesocket(ListenSocket);
		WSACleanup();
		return 1;
	}

	// 清理
	closesocket(ListenSocket);
	WSACleanup();
	return 0;
}

客户端程序

// Client
#ifndef WIN32_LEAN_AND_MEAN
#define WIN32_LEAN_AND_MEAN
#endif
#define DEFAULT_PORT "27015"
#define DEFAULT_BUFLEN 512
#include <WinSock2.h>
#include <WS2tcpip.h>
#include <IPHlpApi.h>
#include <stdio.h>
#pragma comment(lib, "WS2_32.lib")
int main(int argc, char ** argv)
{
	// 初始化 Winsock
	WSADATA wsaData;
	int iResult;
	iResult = WSAStartup(MAKEWORD(2,2),&wsaData);
	if (iResult != 0) {
		printf("WSAStartup failed: %d\n", iResult);
		return 1;
	}

	// 获取连接属性
	struct addrinfo * result = NULL, * ptr = NULL, hints;
	ZeroMemory(&hints, sizeof(hints));
	hints.ai_family = AF_UNSPEC;
	hints.ai_socktype = SOCK_STREAM;
	hints.ai_protocol = IPPROTO_TCP;

	iResult = getaddrinfo("127.0.0.1", DEFAULT_PORT, &hints, &result);
	if (iResult != 0) {
		printf("getaddrinfo failed: %d\n", iResult);
		WSACleanup();
		return 1;
	}

	// 创建 Socket 对象
	ptr = result;
	SOCKET ConnectSocket = INVALID_SOCKET;
	ConnectSocket = socket(ptr->ai_family, ptr->ai_socktype, ptr->ai_protocol);
	if (ConnectSocket == INVALID_SOCKET) {
		printf("Error at socket(): %ld\n", WSAGetLastError());
		freeaddrinfo(result);
		WSACleanup();
		return 1;
	}

	// 链接
	iResult = connect(ConnectSocket, ptr->ai_addr, (int)ptr->ai_addrlen);
	if (iResult == SOCKET_ERROR) {
		closesocket(ConnectSocket);
		ConnectSocket = INVALID_SOCKET;
	}

	// Should really try the next address returned by getaddrinfo
	// if the connect call failed
	// But for this simple example we just free the resources
	// returned by getaddrinfo and print an arror message
	freeaddrinfo(result);

	if (ConnectSocket == INVALID_SOCKET) {
		printf("Unable to connect to server!\n");
		WSACleanup();
		return 1;
	}

	// 发送一些数据
	char * sendbuf = "this is a test";
	char recvbuf[DEFAULT_BUFLEN];
	iResult = send(ConnectSocket, sendbuf, (int)strlen(sendbuf), 0);
	if (iResult == SOCKET_ERROR) {
		printf("send failed: %d\n", WSAGetLastError());
		closesocket(ConnectSocket);
		WSACleanup();
		return 1;
	}

	// 关闭 Socket 对象
	iResult = shutdown(ConnectSocket, SD_SEND);
	if (iResult == SOCKET_ERROR) {
		printf("shutdown failed: %d\n", WSAGetLastError());
		closesocket(ConnectSocket);
		WSACleanup();
		return 1;
	}

	// 清理
	closesocket(ConnectSocket);
	WSACleanup();
	return 0;
}