复制代码 代码如下:
//File Name: Singleton.h
#pragma once

class Singleton
{
private:
CString strGUID;
CString strMapFileGUID;

HANDLE m_hSingleton;

public:
Singleton();
~Singleton();
public:
void AppStart (const HWND & hWnd) const;
};

复制代码 代码如下:
//File Name: Singleton.cpp

#include "stdafx.h"
#include "Singleton.h"

Singleton::Singleton()
{
strGUID = _T("{D727BDB5-F86A-405b-910D-11AD2A4CA76E}");
strMapFileGUID = strGUID + _T("_MapFile");
m_hSingleton = NULL;
}

Singleton::~Singleton()
{
if (m_hSingleton)
{
CloseHandle(m_hSingleton);
m_hSingleton = NULL;
}
}

void Singleton::AppStart(const HWND & hWnd) const
{
HANDLE m_hSingleton = NULL;
m_hSingleton = CreateMutex(NULL, TRUE, strGUID);
RECT rect;

ZeroMemory(&rect, sizeof(rect));
::GetWindowRect(hWnd, &rect);

if (GetLastError() == ERROR_ALREADY_EXISTS)
{
// 打开共享文件
HANDLE hHandle = ::OpenFileMapping(FILE_MAP_ALL_ACCESS, FALSE, strMapFileGUID);
if (hHandle)
{
LPTSTR lpMapAddr = (LPTSTR)::MapViewOfFile(hHandle, FILE_MAP_ALL_ACCESS, 0, 0, 0);
CString strBuffer(lpMapAddr);

HWND hOldWnd = (HWND)_tcstoul(strBuffer, NULL, 10);
::SetForegroundWindow(hOldWnd);

// 取消内核对象的映射
UnmapViewOfFile(hHandle);

CloseHandle(hHandle);

exit(0);
}

}
else // 第一运行程序
{
int nNum = sizeof(HANDLE);

// 创建文件映射内核对象
HANDLE hHandle = ::CreateFileMapping(INVALID_HANDLE_VALUE, NULL, PAGE_READWRITE, 0, sizeof(HANDLE), strMapFileGUID);

if (hHandle)
{
// 拷贝数据到共享文件里
LPTSTR lpMapAddr = (LPTSTR)::MapViewOfFile(hHandle, FILE_MAP_ALL_ACCESS, 0, 0, 0);

CString strBuffer;
strBuffer.Format(_T("%d"), hWnd);

_tcscpy(lpMapAddr, strBuffer);

// 讲写入文件映射缓冲区的所有数据刷新到磁盘；
::FlushViewOfFile(lpMapAddr, strBuffer.GetLength()+1);
}
}
}