An MFC extension library to enable DLL plug-in technology for your application using MESSAGE_MAPs

//
// Module : SINSTANCE.H
// Purpose: Defines the interface for an MFC wrapper class to do instance checking
// Created: PJN / 29-07-1998
// History: PJN / 25-03-2000 Neville Franks made the following changes. Contact nevf@getsoft.com, www.getsoft.com
//                          1. Changed #pragma error to #pragma message. Former wouldn't compile under VC6
//                          2. Replaced above #pragma with #include
//                          3. Added TrackFirstInstanceRunning(), MakeMMFFilename()
//          RIA / 2004      1. Added command line passing to other instance
//
// Copyright (c) 1998 - 2000 by PJ Naughter.  
// All rights reserved.
//
#pragma once

#ifndef __AFXMT_H__
#include "afxmt.h"
#endif

// message sent when sending command line to other running instance
#define	WM_COMMANDLINE		_T("UWM_COMMANDLINE")

class CInstanceChecker : public CObject
{
public:
    //Constructors / Destructors
                    CInstanceChecker();
    virtual         ~CInstanceChecker();

//General functions
	BOOL	        TrackFirstInstanceRunning();
	BOOL	        PreviousInstanceRunning();
	HWND	        ActivatePreviousInstance(CString command_line); 
	CString	        GetCommandLine();
	void	        SetWindowHandle(HWND hwnd);

protected:
	virtual HWND    GetWindowToTrack();
	void	        ReleaseLock();
	LPCTSTR	        MakeMMFFilename();
	CMutex	        m_instanceDataMutex;
	CMutex	        m_executeMutex;
	CSingleLock*    m_pExecuteLock;
    CString         m_productName;
};