#ifndef LimitSingleInstance_H
#define LimitSingleInstance_H

#include <windows.h> 

//this code is from Q243953 in case you lose the article and wonder
//where this code came from...
class CLimitSingleInstance
{
protected:
	DWORD  m_dwLastError;
	HANDLE m_hMutex;
	
public:
	CLimitSingleInstance(TCHAR *strMutexName)
	{
		//be sure to use a name that is unique for this application otherwise
		//two apps may think they are the same if they are using same name for
		//3rd parm to CreateMutex
		m_hMutex = CreateMutex(NULL, FALSE, strMutexName); //do early
		m_dwLastError = GetLastError(); //save for use later...
	}
	
	~CLimitSingleInstance() 
	{
		if (m_hMutex)  //don't forget to close handles...
		{
			CloseHandle(m_hMutex); //do as late as possible
			m_hMutex = NULL; //good habit to be in
		}
	}
	
	BOOL IsAnotherInstanceRunning() 
	{
		return (ERROR_ALREADY_EXISTS == m_dwLastError);
	}
};
#endif