Re: issue with releasing memory from CArry

"Raghavendra" <Raghavendra @discussions.microsoft.com> ha scritto nel
messaggio news:D5F11848-3798-40C8-A4E4-B8048504DE2E@microsoft.com...


First of all, I would suggest to check if you have installed Service Pack 6
for VC++6.


[...]

The above code is not compilable, maybe you did not copy-and-paste from your
editor.

However, you can see at the end of this email a sample MFC code I developed
using CArray which should be like your code; it is compilable and gives no
error/exceptions.

You can attach that code to a button click event handler (and the VoxelCoord
class I wrote is just a testing implementation).


So, you are building a DLL, and you are using not Visual C++ compiler?
I don't have Intel compiler, so I can't give suggestions about that.

About using code inside a DLL, you may check that every object that you
create on the heap from the DLL is also destroyed from the DLL, and every
object that you create on the heap from the exe is also destroyed from the
exe.
Moreover you should pay attention to passing C++ objects at DLL interface;
in that case, you should also pay attention that both DLL and EXE are built
using the same compiler (IMHO, the more robust technology to pass objects
between EXEs and DLLs is COM).

Moreoever, there are also STL containers. Some programmers prefer MFC
containers, other prefer STL containers. You can use STL containers in MFC
code, too.

However, if you are using VC++6, you should apply Dinkumware patches to STL,
or use STLport, because STL implementation of VC6 has bugs.

Using STL containers is easy, and STL containers are very well "composible"
(i.e. you can easily build STL containers storing other STL containers) e.g.

  #include <vector> // vector container

  typedef std::vector< VoxelCoord > VoxelCoordArray;
  typedef std::vector< VoxelCoordArray > ArrayOfVoxelCoordArray;

  // Create an array of size specified in the constructor
  ArrayOfVoxelCoordArray v( PIXVOXCOORDARRLEN );

  // ... v[i] is a VoxelCoordArray:
  // can add VoxelCoord instances to it
  v[i].push_back( VoxelCoord(...) );
  v[i].push_back( VoxelCoord(...) );

  // You don't need cleanup with pointers! :)

And here's the testing CArray-based code:

<code>

// Just a test implementation...
class VoxelCoord
{
public:

    VoxelCoord()
    {
        TRACE(_T("VoxelCoord default Ctor"));

        X = 0;
        Y = 0;
    }

    VoxelCoord( double x, double y )
        : X(x), Y(y)
    {
        TRACE(_T("VoxelCoord ctor with x,y"));
    }

    ~VoxelCoord()
    {
        TRACE(_T("VoxelCoord Destructor"));

        X = 0;
        Y = 0;
        return;
    }

    double X;
    double Y;
};

void CTestReleaseDlg::OnBnClickedButton1()
{
    // *** TEST ***

    // A CArray storing VoxelCooord instances
    typedef CArray< VoxelCoord, VoxelCoord & > VoxCoordArray;

    // Pointer to an array storing VoxelCoord instances
    typedef VoxCoordArray * VoxCoordArrayPtr;

    //
    // Create data structure
    //

    // Allocate a bunch of VoxelCoordArray pointers
    static const int PIXVOXCOORDARRLEN = 5;
    VoxCoordArrayPtr * myPixVoxCoordArray = new
VoxCoordArrayPtr[PIXVOXCOORDARRLEN];

    // Clear pointers to NULL
    for ( int ii = 0; ii < PIXVOXCOORDARRLEN; ii++ )
    {
        myPixVoxCoordArray[ii] = NULL;
    }

    // Create array instance for each pointer
    for ( int i = 0; i < PIXVOXCOORDARRLEN; i++ )
    {
        myPixVoxCoordArray[i] = new VoxCoordArray;
    }

    //
    // Add something ...
    //
    myPixVoxCoordArray[2]->Add( VoxelCoord() );
    myPixVoxCoordArray[2]->Add( VoxelCoord(2,0) );
    myPixVoxCoordArray[4]->Add( VoxelCoord(-1,3) );

    //
    // Deallocate
    //
    if ( myPixVoxCoordArray )
    {
        for ( int i = PIXVOXCOORDARRLEN-1; i >= 0; i-- )
        {
            if ( myPixVoxCoordArray[i] )
            {
                myPixVoxCoordArray[i]->RemoveAll();
                delete myPixVoxCoordArray[i];
                myPixVoxCoordArray[i] = NULL;
            }
        }

        delete [] myPixVoxCoordArray;
        myPixVoxCoordArray = NULL;
    }

}

</code>

Giovanni