C / C++ / MFC

class CMutexAccesor
{
  public:
    CMutexAccesor(LPCTSTR lpstrMutexName){
      res=(mutex=CreateMutex(NULL,FALSE,lpstrMutexName))!=NULL;
      if(res){
        // Wait up to 4 secs for locking
        res=WaitForSingleObject(mutex,4000)==WAIT_OBJECT_0;
        if(!res)CloseHandle(mutex);
      }
    }
    ~CMutexAccesor(){
      if(res){
        ReleaseMutex(mutex);
        CloseHandle(mutex);
      }
    }

    BOOL res;

  private:
    HANDLE mutex;
};

class CTester(prsSomeTable)
{
	UpdateDB()
	{
		CMutexAccessor *pMut;
		pMut = new CMutexAccessor();
		prs->Edit();
		prs->x = 2;
		prs->Update();
		delete pMut;
	}
};

class CTester(prsSomeTable)
{
	UpdateDB()
	{
		CMutexAccessor *pMut;

		prs->Edit();
		prs->x = 2;
		pMut = new CMutexAccessor();
		prs->Update();
		delete pMut;
	}
};

UpdateDB()
	{
		CMutexAccessor mut("MYONEANDONLYNAMENOONECAMETOFIGUREOUTBEFORE");
		prs->Edit();
		prs->x = 2;
		pMut = new CMutexAccessor();
		prs->Update();
	}

class CRequests : public CRecordset
{
public:
	CRequests(CDatabase* pDatabase = NULL);
	DECLARE_DYNAMIC(CRequests)

// Field/Param Data
	//{{AFX_FIELD(CRequests, CRecordset)
	long	m_ID;
	CString	m_SERVICE_TYPE;
clip for brevity
	//}}AFX_FIELD
	CMutexAccesor *pMutex;
#define DBMUTEX "AFX_REQUESTS_3B2738B5_A172_11D5_9FCB_00B0D081C96F"

// Overrides
	// ClassWizard generated virtual function overrides
	//{{AFX_VIRTUAL(CRequests)
	public:
	virtual CString GetDefaultConnect();    // Default connection string
	virtual CString GetDefaultSQL();    // Default SQL for Recordset
	virtual void DoFieldExchange(CFieldExchange* pFX);  // RFX support
	//}}AFX_VIRTUAL
	virtual void AddNew()
	{
		try 
		{
			pMutex = new CMutexAccesor(DBMUTEX);
			CRecordset::AddNew();
		}
		catch (CDBException *e)
		{
			if (pMutex)
			{
				if (pMutex) delete pMutex;
				pMutex = NULL;
			}
			throw e;
		}
		if (pMutex) delete pMutex;

	}

	virtual void Edit()
	{
		try
		{
			pMutex = new CMutexAccesor(DBMUTEX);
			CRecordset::Edit();
		}
		catch (CDBException *e)
		{
			if (pMutex)
			{
				if (pMutex) delete pMutex;
				pMutex = NULL;
			}
			throw e;
		}
		if (pMutex) delete pMutex;
	}

	virtual BOOL Update()
	{
		BOOL bRet;
		try
		{
			bRet = CRecordset::Update();
		}
		catch (CDBException *e)
		{
			delete pMutex;
			throw e;
		}
		delete pMutex;
		return bRet;
	}
	
	void AbandonUpdate()
	{
		if (pMutex) delete pMutex;
	}

};

virtual void AddNew()
{
	CMutexAccesor(DBMUTEX) mut;
	CRecordset::AddNew();
}
virtual void Edit(){
	CMutexAccesor(DBMUTEX) mut;
	CRecordset::Edit();
}

GetEditCtrl().SetReadOnly(TRUE);

• (Release) Single-Threaded
  
• (Release) Multithreaded
  
• (Release) Multithreaded DLL
  
• Debug Single-Threaded
  
• Debug Multithreaded
  
• Debug Multithreaded DLL
  

1. Fire up a browser and visit www.google.com.
   
   
2. In the search box, type "multidimensional arrays". (Omit the quotes.)
   
   
3. You'll see a page of links. Click on the second link (www.eskimo.com/~scs/cclass/notes/sx4ba.html).
   
   
4. Read the page content.

Todd Smith

#include "memory.h"
#include "new.h"
//
void main()
{
	int x = 4, y = 7, z = 9; // 3D array
	int i, j, k;
//
	// Allocate memory
	int nSize = x * y * z * sizeof(int);
	int* p = (int*)::operator new(x * y * z * sizeof(int));
	int* q = p; // Used while creating the array
	::memset(p, 0, nSize); // Initialize all array data to zero
//
	// Create the array
	int*** a = new int**[x];
	for (i = 0; i < x; i++)
	{
		a[i] = new int*[y];
		for (j = 0; j < y; j++)
		{
			a[i][j] = new (q) int[z];
			q += z;
		}
	}
//
	// Set values to all values in the array
	for (i = 0; i < x; i++)
	{
		for (j = 0; j < y; j++)
		{
			for (k = 0; k < z; k++)
			{
				a[i][j][k] = i + (j * x) + (k * x * y);
			}
		}
	}	
//
	// Deallocate the array -  NB! No destruction
	for (i = 0; i < x; i++)
	{
		delete[] a[i];
	}
	delete[] a;	
	::operator delete(p);
}