完成例程

#include <WINSOCK2.H>
#include <stdio.h>
#pragma comment(lib, "ws2_32.lib")
#define PORT  5150
#define MSGSIZE  1024

typedef struct 
{
	WSAOVERLAPPED overlap;
	WSABUF        Buffer;
	char          szMessage[MSGSIZE];
	DWORD         NumberOfBytesRecvd;
	DWORD         Flags;
	SOCKET        sClient;
} PER_IO_OPERATION_DATA, *LPPER_IO_OPERATION_DATA;

void CALLBACK CompletionRoutine(DWORD dwError, DWORD cbTransferred, LPWSAOVERLAPPED lpOverlapped, DWORD dwFlags);
SOCKET g_sNewClientConnection;


int main(int argc, char* argv[])
{
	WSADATA wsaData;
	SOCKET sListen;
	SOCKADDR_IN local, client;
	DWORD dwThreadId;
	int iAddrSize = sizeof(SOCKADDR_IN);
	// Initialize windows socket library
	WSAStartup(0x0202, &wsaData);
	// Create listening socket
	sListen = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
	// Bind
	local.sin_family = AF_INET;
	local.sin_addr.S_un.S_addr = htonl(INADDR_ANY);
	local.sin_port = htons(PORT);
	bind(sListen, (sockaddr*)&local, sizeof(SOCKADDR_IN));
	// Listen
	listen(sListen, 3);
	while (TRUE)
	{
		// Accept a connection
		g_sNewClientConnection = accept(sListen, (sockaddr*)&client, &iAddrSize);


		LPPER_IO_OPERATION_DATA lpPerIOData = NULL;
		lpPerIOData = (LPPER_IO_OPERATION_DATA)HeapAlloc(
			GetProcessHeap(),
			HEAP_ZERO_MEMORY,
			sizeof(PER_IO_OPERATION_DATA));

		//lpPerIOData = new PER_IO_OPERATION_DATA();
		int i = sizeof(lpPerIOData->szMessage);
		lpPerIOData->Buffer.len = MSGSIZE;
		lpPerIOData->Buffer.buf = lpPerIOData->szMessage;
		lpPerIOData->sClient = g_sNewClientConnection;
		lpPerIOData->Flags = 0;
		int code = WSARecv(lpPerIOData->sClient,
			&lpPerIOData->Buffer,
			1,
			&lpPerIOData->NumberOfBytesRecvd,
			&lpPerIOData->Flags,
			&lpPerIOData->overlap,
			CompletionRoutine);
		printf("Accepted client:%s:%d\n", inet_ntoa(client.sin_addr), ntohs(client.sin_port));		

	}
	return 0;
}


void CALLBACK CompletionRoutine(DWORD dwError, DWORD cbTransferred, LPWSAOVERLAPPED lpOverlapped, DWORD dwFlags)
{
	LPPER_IO_OPERATION_DATA lpPerIOData = (LPPER_IO_OPERATION_DATA)lpOverlapped;
	if (dwError != 0 || cbTransferred == 0)
	{
		// Connection was closed by client
		closesocket(lpPerIOData->sClient);
		HeapFree(GetProcessHeap(), 0, lpPerIOData);
	}
	else
	{
		lpPerIOData->szMessage[cbTransferred] = '\0';
		send(lpPerIOData->sClient, lpPerIOData->szMessage, cbTransferred, 0);
		// Launch another asynchronous operation
		memset(&lpPerIOData->overlap, 0, sizeof(WSAOVERLAPPED));
		lpPerIOData->Buffer.len = MSGSIZE;
		lpPerIOData->Buffer.buf = lpPerIOData->szMessage;
		lpPerIOData->Flags = 0;
		WSARecv(lpPerIOData->sClient,
			&lpPerIOData->Buffer,
			1,
			&lpPerIOData->NumberOfBytesRecvd,
			&lpPerIOData->Flags,
			&lpPerIOData->overlap,
			CompletionRoutine);
	}
}