采用Windows完成端口写的服务器

//完成端口例子
#include <winsock2.h>
#include <windows.h>
#include <stdio.h>

#define PORT 8090
#define DATA_BUFSIZE 8192

#pragma comment(lib, "Ws2_32")

typedef struct
//这个玩意就是灌数据，取数据的一个自定义数据结构
//和那个wm_data差不了多少，不过就是老要塞一个OverLapped结构
{
	OVERLAPPED Overlapped;
	WSABUF DataBuf;
	CHAR Buffer[DATA_BUFSIZE];
	//发送字节数
	DWORD BytesSEND;                                 
	DWORD BytesRECV;
} PER_IO_OPERATION_DATA, * LPPER_IO_OPERATION_DATA;


typedef struct
{
	SOCKET Socket;
} PER_HANDLE_DATA, * LPPER_HANDLE_DATA;


DWORD WINAPI ServerWorkerThread(LPVOID CompletionPortID);

void main(void)
{
	SOCKADDR_IN InternetAddr;
	SOCKET Listen;
	SOCKET Accept;
	//完成端口
	HANDLE CompletionPort;
	//系统信息，用于获取当前系统的CPU核数
	SYSTEM_INFO SystemInfo;
	LPPER_HANDLE_DATA PerHandleData;
	LPPER_IO_OPERATION_DATA PerIoData;
	int i;
	DWORD RecvBytes;
	DWORD Flags;
	DWORD ThreadID;
	WSADATA wsaData;
	DWORD Ret;

	if ((Ret = WSAStartup(0x0202, &wsaData)) != 0)
	{
		printf("WSAStartup failed with error %d\n", Ret);
		return;
	}

	//创建完成端口
	if ((CompletionPort = CreateIoCompletionPort(INVALID_HANDLE_VALUE, NULL, 0, 0)) == NULL)
	{
		printf("CreateIoCompletionPort failed with error: %d\n", GetLastError());
		return;
	}
	//获取系统信息
	GetSystemInfo(&SystemInfo);

	//双倍CPU运行
	for (i = 0; i < SystemInfo.dwNumberOfProcessors * 2; i++)
	{
		//创建线程句柄
		HANDLE ThreadHandle;

		//完成端口挂到线程上面来了，就像管子把灌数据的和读数据的两头都连上了,           
		if ((ThreadHandle = CreateThread(NULL, 0, ServerWorkerThread, CompletionPort,
			0, &ThreadID)) == NULL)
		{
			printf("CreateThread() failed with error %d\n", GetLastError());
			return;
		}
		CloseHandle(ThreadHandle);
	}

	//启动一个监听socket ，监听设置为重叠(OVERLAPPED),只有在服务端才有必要设置
	if ((Listen = WSASocket(AF_INET, SOCK_STREAM, 0, NULL, 0,
		WSA_FLAG_OVERLAPPED)) == INVALID_SOCKET)
	{
		printf("WSASocket() failed with error %d\n", WSAGetLastError());
		return;
	}

	InternetAddr.sin_family = AF_INET;
	//监听所有IP发送来的消息
	InternetAddr.sin_addr.s_addr = htonl(INADDR_ANY);
	//设定监听端口
	InternetAddr.sin_port = htons(PORT);

	//将Socket设置为监听
	if (bind(Listen, (PSOCKADDR)&InternetAddr, sizeof(InternetAddr)) == SOCKET_ERROR)
	{
		printf("bind() failed with error %d\n", WSAGetLastError());
		return;
	}

	//开始监听
	//SOMAXCONN : Maximum queue length specifiable by listen
	if (listen(Listen, SOMAXCONN) == SOCKET_ERROR)
	{
		printf("listen() failed with error %d\n", WSAGetLastError());
		return;
	}

	// 监听端口打开，就开始在这里循环，一有socket连上，WSAAccept就创建一个socket，
	// 这个socket 又和完成端口联上,
	
	// 嘿嘿，完成端口第二次调用那个createxxx函数，为什么，留给人思考思考可能更深刻，
	// 反正这套路得来2次，
	// 完成端口completionport和accept socket挂起来了，
	while (TRUE)
	{
		//主线程跑到这里就等啊等啊，但是线程却开工了，
		if ((Accept = WSAAccept(Listen, NULL, NULL, NULL, 0)) == SOCKET_ERROR)
		{
			printf("WSAAccept() failed with error %d\n", WSAGetLastError());
			return;
		}

		if ((PerHandleData = (LPPER_HANDLE_DATA)GlobalAlloc(GPTR, sizeof(PER_HANDLE_DATA))) == NULL)
		{
			printf("GlobalAlloc() failed with error %d\n", GetLastError());
			return;
		}
		PerHandleData->Socket = Accept;

	    //把这头和完成端口completionPort连起来
	    //就像你把漏斗接到管子口上,开始要灌数据了
		//虽然是同一个方法，但是入参不同功能也不同
		if (CreateIoCompletionPort((HANDLE)Accept, CompletionPort, (DWORD)PerHandleData,
			0) == NULL)
		{
			printf("CreateIoCompletionPort failed with error %d\n", GetLastError());
			return;
		}

		//清管子的数据结构,准备往里面灌数据
		if ((PerIoData = (LPPER_IO_OPERATION_DATA)GlobalAlloc(GPTR, sizeof(PER_IO_OPERATION_DATA))) == NULL)
		{
			printf("GlobalAlloc() failed with error %d\n", GetLastError());
			return;
		}

		ZeroMemory(&(PerIoData->Overlapped), sizeof(OVERLAPPED));
		PerIoData->BytesSEND = 0;
		PerIoData->BytesRECV = 0;
		PerIoData->DataBuf.len = DATA_BUFSIZE;
		PerIoData->DataBuf.buf = PerIoData->Buffer;

		Flags = 0;

		//  accept接到了数据，就放到PerIoData中,而perIoData又通过线程中的函数取出,
		if (WSARecv(Accept, &(PerIoData->DataBuf), 1, &RecvBytes, &Flags,
			&(PerIoData->Overlapped), NULL) == SOCKET_ERROR)
		{
			if (WSAGetLastError() != ERROR_IO_PENDING)
			{
				printf("WSARecv() failed with error %d\n", WSAGetLastError());
				return;
			}
		}
	}
	//不会执行到这里
	printf("Main Thread End\n");
}

//线程一但调用，就老在里面循环，
//注意，传入的可是完成端口啊，就是靠它去取出管子中的数据
DWORD WINAPI ServerWorkerThread(LPVOID CompletionPortID)
{
	HANDLE CompletionPort = (HANDLE)CompletionPortID;

	DWORD BytesTransferred;
	LPOVERLAPPED Overlapped;
	LPPER_HANDLE_DATA PerHandleData;
	LPPER_IO_OPERATION_DATA PerIoData;
	DWORD SendBytes, RecvBytes;
	DWORD Flags;
	

	while (TRUE)
	{
		//在这里检查完成端口部分的数据buf区，数据来了吗？
		// 这个函数参数要看说明，
		// PerIoData 就是从管子流出来的数据,
		//PerHandleData 也是从管子里取出的，是何时塞进来的，
	    //就是在建立第2次createIocompletionPort时
		if (GetQueuedCompletionStatus(CompletionPort, &BytesTransferred,
			(LPDWORD)&PerHandleData, (LPOVERLAPPED*)&PerIoData, INFINITE) == 0)
		{
			printf("GetQueuedCompletionStatus failed with error %d\n", GetLastError());
			return 0;
		}

		// 检查数据传送完了吗
		if (BytesTransferred == 0)
		{
			printf("Closing socket %d\n", PerHandleData->Socket);
			printf("Receive Message%s\n", PerIoData->Buffer);

			if (closesocket(PerHandleData->Socket) == SOCKET_ERROR)
			{
				printf("closesocket() failed with error %d\n", WSAGetLastError());
				return 0;
			}
			GlobalFree(PerHandleData);
			GlobalFree(PerIoData);
			continue;
		}

	   //看看管子里面有数据来了吗？= 0，那是刚收到数据
		if (PerIoData->BytesRECV == 0)
		{
			PerIoData->BytesRECV = BytesTransferred;
		}

		Flags = 0;
		ZeroMemory(&(PerIoData->Overlapped), sizeof(OVERLAPPED));

		PerIoData->DataBuf.len = DATA_BUFSIZE;
		PerIoData->DataBuf.buf = PerIoData->Buffer;

		if (WSARecv(PerHandleData->Socket, &(PerIoData->DataBuf), 1, &RecvBytes, &Flags,
			&(PerIoData->Overlapped), NULL) == SOCKET_ERROR)
		{
			if (WSAGetLastError() != ERROR_IO_PENDING)
			{
				//如果已经读完了
				printf("WSARecv() failed with error %d\n", WSAGetLastError());
				return 0;
			}
		}
	}
}

我用的VS2019，解决方案配置是Win32。