【Windows核心编程】Application Instance示例程序

本篇文章会以 Application Instance 示例程序为例讲到如何在同一个可执行文件或DLL的多个实例间共享静态数据。同时会接触一些消息相关的知识。

每个.exe文件或DLL文件映像由许多段组成。按照惯例，每个标准的段名都以点号开始。例如在编译程序的时候，编译器会将代码放在一个.text的段中。此外编译器还会将未初始化的数据放在.bss段中，将已经初始化的数据放在.data段中。

每个段可以指定属性，比如可读、可写、可执行、可共享。

这里我们说的可共享就是关闭了写时复制机制，通过这种方法可以让.exe或DLL在多个实例间共享数据。

#include <Windows.h>

// 整个系统的消息，对应用程序来说应该是独一无二的
// The system-wide window message, unique to the application
UINT g_uMsgAppInstCountUpdate = WM_APP + 123;

//创建一个Shared段，并存放一个数据 - 注意，这个数据必须是初始化的
#pragma data_seg("Shared")
volatile LONG g_lApplicationInstances = 0;
#pragma data_seg()

// 告诉链接器，让 Shared 段属性为 可读可写可共享
// Tell the linker to make the Shared section readable, writable, and shared.
#pragma comment(linker ,"/Section:Shared,RWS")

LRESULT CALLBACK WinSunProc(
	HWND hWnd,
	UINT uMsg,
	WPARAM wParam,
	LPARAM lParam
	);

INT WINAPI WinMain(
	HINSTANCE hInstance,
	HINSTANCE hPrevInstance,
	LPSTR lCmdLine,
	INT nCmdShow
	)
{
	//设计窗口类
	WNDCLASS wndcls;
	wndcls.cbClsExtra = 0;
	wndcls.cbWndExtra = 0;
	wndcls.hbrBackground = (HBRUSH)GetStockObject(COLOR_WINDOWFRAME);
	wndcls.hCursor = LoadCursor(NULL, IDC_ARROW);
	wndcls.hIcon = LoadIcon(NULL, IDI_APPLICATION);
	wndcls.hInstance = hInstance;
	wndcls.lpfnWndProc = WinSunProc;
	wndcls.lpszClassName = TEXT("NormalWindow");
	wndcls.lpszMenuName = NULL;
	wndcls.style = CS_HREDRAW | CS_VREDRAW;

	//注册窗口类
	ATOM nAtom = 0;
	nAtom = RegisterClass(&wndcls);
	if(nAtom == 0)
	{
		MessageBox(NULL, TEXT("Register Failed"), TEXT("Error"), MB_OK | MB_ICONERROR);
		return FALSE;
	}

	//注册消息
	g_uMsgAppInstCountUpdate = RegisterWindowMessage(TEXT("MsgAppInstCountUpdate"));

	//创建窗口
	HWND hwnd;
	hwnd = CreateWindow(TEXT("NormalWindow"), TEXT("ApplicationInstance"), WS_OVERLAPPEDWINDOW,
						300, 300, 600, 400, NULL, NULL, hInstance, NULL);
	if(hwnd == NULL)
	{
		MessageBox(NULL, TEXT("Create Window Failed"), TEXT("Error"), MB_OK | MB_ICONERROR);
		return FALSE;
	}

	//显示窗口
	ShowWindow(hwnd, SW_SHOWNORMAL);

	//刷新窗口
	UpdateWindow(hwnd);

	//消息循环
	BOOL bRet;
	MSG msg;
	while(bRet = GetMessage(&msg, hwnd, 0, 0))
	{
		if(bRet == -1)
		{
			// handle the error and possibly exit
			return -1;
		}
		else
		{
			TranslateMessage(&msg);
			DispatchMessage(&msg);
		}
	}
	return msg.wParam;
}

LRESULT CALLBACK WinSunProc(
	HWND hwnd,
	UINT uMsg,
	WPARAM wParam,
	LPARAM lParam
	)
{
	//收到我们指定的消息
	if(uMsg == g_uMsgAppInstCountUpdate)
	{
		RECT rect;		//重绘窗口用到
		//获取窗口大小
		GetClientRect(hwnd, &rect);
		//要求重绘
		InvalidateRect(hwnd, &rect, TRUE);
		//更新窗口
		UpdateWindow(hwnd);
		
		return 0;
	}

	wchar_t A[30];
	switch(uMsg)
	{
		case WM_CREATE:
			// 有一个新的应用程序在运行
			// There is another instance of this application running
			InterlockedExchangeAdd(&g_lApplicationInstances, 1);

			//发送消息 - 通知更新窗口
			PostMessage(HWND_BROADCAST, g_uMsgAppInstCountUpdate, 0, 0);

			break;

		case WM_PAINT:	////绘制消息
			HDC hDC;
			PAINTSTRUCT ps;
			hDC = BeginPaint(hwnd, &ps);

			wsprintf(A, TEXT("应用程序运行数量：%d"), g_lApplicationInstances);
			TextOut(hDC, 10, 10, A, lstrlen(A));

			EndPaint(hwnd, &ps);
			break;

		case WM_CLOSE:	////关闭按钮消息
			if(IDYES == MessageBox(hwnd, TEXT("是否真的退出?"), TEXT("QuitMessage"), MB_YESNO))
			{
				DestroyWindow(hwnd);
			}
			break;

		case WM_DESTROY:////当窗口销毁时，会调用WinSunProc
			
			// 整个应用程序实例要退出了
			// This instance of the application is terminating
			InterlockedExchangeAdd(&g_lApplicationInstances, -1);

			// 让其他应用程序更新他们的显示信息
			// Have all other instances update their display
			PostMessage(HWND_BROADCAST, g_uMsgAppInstCountUpdate, 0, 0);

			PostQuitMessage(0);////发送一个退出消息
			break;

		default:
			return DefWindowProc(hwnd, uMsg, wParam, lParam);
	}

	return 0;
}

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#include <Windows.h>

// 整个系统的消息，对应用程序来说应该是独一无二的

// The system-wide window message, unique to the application

UINT g_uMsgAppInstCountUpdate = WM_APP + 123;

//创建一个Shared段，并存放一个数据 - 注意，这个数据必须是初始化的

#pragma data_seg("Shared")

volatile LONG g_lApplicationInstances = 0;

#pragma data_seg()

// 告诉链接器，让 Shared 段属性为可读可写可共享

// Tell the linker to make the Shared section readable, writable, and shared.

#pragma comment(linker ,"/Section:Shared,RWS")

LRESULT CALLBACK WinSunProc(

HWND hWnd,

UINT uMsg,

WPARAM wParam,

LPARAM lParam

);

INT WINAPI WinMain(

HINSTANCE hInstance,

HINSTANCE hPrevInstance,

LPSTR lCmdLine,

INT nCmdShow

)

{

//设计窗口类

WNDCLASS wndcls;

wndcls.cbClsExtra = 0;

wndcls.cbWndExtra = 0;

wndcls.hbrBackground = (HBRUSH)GetStockObject(COLOR_WINDOWFRAME);

wndcls.hCursor = LoadCursor(NULL, IDC_ARROW);

wndcls.hIcon = LoadIcon(NULL, IDI_APPLICATION);

wndcls.hInstance = hInstance;

wndcls.lpfnWndProc = WinSunProc;

wndcls.lpszClassName = TEXT("NormalWindow");

wndcls.lpszMenuName = NULL;

wndcls.style = CS_HREDRAW | CS_VREDRAW;

//注册窗口类

ATOM nAtom = 0;

nAtom = RegisterClass(&wndcls);

if(nAtom == 0)

{

MessageBox(NULL, TEXT("Register Failed"), TEXT("Error"), MB_OK | MB_ICONERROR);

return FALSE;

}

//注册消息

g_uMsgAppInstCountUpdate = RegisterWindowMessage(TEXT("MsgAppInstCountUpdate"));

//创建窗口

HWND hwnd;

hwnd = CreateWindow(TEXT("NormalWindow"), TEXT("ApplicationInstance"), WS_OVERLAPPEDWINDOW,

300, 300, 600, 400, NULL, NULL, hInstance, NULL);

if(hwnd == NULL)

{

MessageBox(NULL, TEXT("Create Window Failed"), TEXT("Error"), MB_OK | MB_ICONERROR);

return FALSE;

}

//显示窗口

ShowWindow(hwnd, SW_SHOWNORMAL);

//刷新窗口

UpdateWindow(hwnd);

//消息循环

BOOL bRet;

MSG msg;

while(bRet = GetMessage(&msg, hwnd, 0, 0))

{

if(bRet == -1)

{

// handle the error and possibly exit

return -1;

}

else

{

TranslateMessage(&msg);

DispatchMessage(&msg);

}

return msg.wParam;

}

LRESULT CALLBACK WinSunProc(

HWND hwnd,

UINT uMsg,

WPARAM wParam,

LPARAM lParam

)

{

//收到我们指定的消息

if(uMsg == g_uMsgAppInstCountUpdate)

{

RECT rect; //重绘窗口用到

//获取窗口大小

GetClientRect(hwnd, &rect);

//要求重绘

InvalidateRect(hwnd, &rect, TRUE);

//更新窗口

UpdateWindow(hwnd);

return 0;

}

wchar_t A[30];

switch(uMsg)

{

case WM_CREATE:

// 有一个新的应用程序在运行

// There is another instance of this application running

InterlockedExchangeAdd(&g_lApplicationInstances, 1);

//发送消息 - 通知更新窗口

PostMessage(HWND_BROADCAST, g_uMsgAppInstCountUpdate, 0, 0);

break;

case WM_PAINT: ////绘制消息

HDC hDC;

PAINTSTRUCT ps;

hDC = BeginPaint(hwnd, &ps);

wsprintf(A, TEXT("应用程序运行数量：%d"), g_lApplicationInstances);

TextOut(hDC, 10, 10, A, lstrlen(A));

EndPaint(hwnd, &ps);

break;

case WM_CLOSE: ////关闭按钮消息

if(IDYES == MessageBox(hwnd, TEXT("是否真的退出?"), TEXT("QuitMessage"), MB_YESNO))

{

DestroyWindow(hwnd);

}

break;

case WM_DESTROY:////当窗口销毁时，会调用WinSunProc

// 整个应用程序实例要退出了

// This instance of the application is terminating

InterlockedExchangeAdd(&g_lApplicationInstances, -1);

// 让其他应用程序更新他们的显示信息

// Have all other instances update their display

PostMessage(HWND_BROADCAST, g_uMsgAppInstCountUpdate, 0, 0);

PostQuitMessage(0);////发送一个退出消息

break;

default:

return DefWindowProc(hwnd, uMsg, wParam, lParam);

}

return 0;

}

代码大致就是这样…

除了WinMain程序套路之外，还有就是注册消息…发送接收消息。

【Windows核心编程】Application Instance示例程序

Tagged on: Win32