Hi,

I'm sorry in advance for a possibly stupid question, but I'm very new to
..net.
I have old code in C++ that should be implemented in a .net environment.
The code has a class which creates a Direc3D object in the constructor
and releases the Direct3D object in the destructor.

class bar
{
public:
bar()
{
m_pD3D = Direct3DCreate9(D3D_SDK_VERSION);
}

~bar()
{
m_pD3D->Release();
}

private:
IDirect3D9 *m_pD3D;
};

Now I want to make this class garbage collected, so I change the class
to: ref class bar and instantiate it with gcnew.

But as I already know, the destructor will no longer be called, even
when the object is destroyed by the garbage collector (in this case,
when the program is closed). So my m_pD3D object will never be released.

The problem gets worse for the project when this happens to a CTexture
class which implements a IDirect3DTexture9* object that is released in
the destructor. Textures are created and released throughout the running
process.

Can anyone tell me how you can change this so that everything of directx
is also garbage collected?

Is there a way that I can change: IDirect3DTexture9 *m_pTex to
IDirect3DTexture9 ^m_pTex or something like that?

Or, how else should I handle the destruction code?

Thanks,
Dirk.

Hi Dirk,

"Dirk Schippers" wrote:

>
> Or, how else should I handle the destruction code?
>

Here's a good blog post, that explains, how C++/CLI implements the
disposable interface:
http://blogs.thinktecture.com/cnagel...10/414477.aspx

To simplify the usage of com smart pointers, I'm using
msclr::com:tr

To simplify the usage of pointers to native resources, I'm using
CAutoNativePtr
See here:
http://www.codeproject.com/KB/mcpp/CAutoNativePtr.aspx

I can also recommend Nish's book "C++/CLI in Action". This saved me days of
searching for a solution...

Dirk Schippers wrote:
> Hi,
>
> I'm sorry in advance for a possibly stupid question, but I'm very new
> to .net.
> I have old code in C++ that should be implemented in a .net
> environment. The code has a class which creates a Direc3D object in
> the constructor and releases the Direct3D object in the destructor.
>
> class bar
> {
> public:
> bar()
> {
> m_pD3D = Direct3DCreate9(D3D_SDK_VERSION);
> }
>
> ~bar()
> {
> m_pD3D->Release();
> }
>
> private:
> IDirect3D9 *m_pD3D;
> };
>
> Now I want to make this class garbage collected, so I change the class
> to: ref class bar and instantiate it with gcnew.
>
> But as I already know, the destructor will no longer be called, even
> when the object is destroyed by the garbage collector (in this case,
> when the program is closed). So my m_pD3D object will never be
> released.
>
> The problem gets worse for the project when this happens to a CTexture
> class which implements a IDirect3DTexture9* object that is released in
> the destructor. Textures are created and released throughout the
> running process.
>
> Can anyone tell me how you can change this so that everything of
> directx is also garbage collected?
>
> Is there a way that I can change: IDirect3DTexture9 *m_pTex to
> IDirect3DTexture9 ^m_pTex or something like that?
>
> Or, how else should I handle the destruction code?

The finalizer is missing (!bar). Documentation:
http://msdn.microsoft.com/en-us/library/ms177197.aspx


(Incomplete) Example of one of my managed wrapper classes:

Declaration:
public ref class IndexBuffer
{
public:
IntPtr Lock(
UINT OffsetToLock,
UINT SizeToLock,
LockFlags Flags
);

void Unlock();

internal:
LPDIRECT3DINDEXBUFFER9 native;
IndexBuffer(LPDIRECT3DINDEXBUFFER9 native);
~IndexBuffer();
!IndexBuffer();
};

Implementation:
IndexBuffer::~IndexBuffer() {this->!IndexBuffer();}
IndexBuffer::!IndexBuffer() {this->native->Release();}


Armin

Armin Zingler wrote:
> Dirk Schippers wrote:
>> Hi,
>>
>> I'm sorry in advance for a possibly stupid question, but I'm very new
>> to .net.
>> I have old code in C++ that should be implemented in a .net
>> environment. The code has a class which creates a Direc3D object in
>> the constructor and releases the Direct3D object in the destructor.
>>
>> class bar
>> {
>> public:
>> bar()
>> {
>> m_pD3D = Direct3DCreate9(D3D_SDK_VERSION);
>> }
>>
>> ~bar()
>> {
>> m_pD3D->Release();
>> }
>>
>> private:
>> IDirect3D9 *m_pD3D;
>> };
>>
>> Now I want to make this class garbage collected, so I change the
>> class to: ref class bar and instantiate it with gcnew.
>>
>> But as I already know, the destructor will no longer be called, even
>> when the object is destroyed by the garbage collector (in this case,
>> when the program is closed). So my m_pD3D object will never be
>> released.
>>
>> The problem gets worse for the project when this happens to a
>> CTexture class which implements a IDirect3DTexture9* object that is
>> released in the destructor. Textures are created and released
>> throughout the running process.
>>
>> Can anyone tell me how you can change this so that everything of
>> directx is also garbage collected?
>>
>> Is there a way that I can change: IDirect3DTexture9 *m_pTex to
>> IDirect3DTexture9 ^m_pTex or something like that?
>>
>> Or, how else should I handle the destruction code?
>
> The finalizer is missing (!bar). Documentation:
> http://msdn.microsoft.com/en-us/library/ms177197.aspx
>
>
> (Incomplete) Example of one of my managed wrapper classes:
>
> Declaration:
> public ref class IndexBuffer
> {
> public:
> IntPtr Lock(
> UINT OffsetToLock,
> UINT SizeToLock,
> LockFlags Flags
> );
>
> void Unlock();
>
> internal:
> LPDIRECT3DINDEXBUFFER9 native;
> IndexBuffer(LPDIRECT3DINDEXBUFFER9 native);
> ~IndexBuffer();
> !IndexBuffer();
> };
>
> Implementation:
> IndexBuffer::~IndexBuffer() {this->!IndexBuffer();}
> IndexBuffer::!IndexBuffer() {this->native->Release();}

Does C++/CLI automatically class GC::SuppressFinalize(this), or is there a
chance of double free here? As well, there's nothing stopping a non-C++
client from calling Dispose more than once, so I think it is important to
add logic to avoid the double free.

>
>
> Armin

Ben Voigt [C++ MVP] wrote:
>> Implementation:
>> IndexBuffer::~IndexBuffer() {this->!IndexBuffer();}
>> IndexBuffer::!IndexBuffer() {this->native->Release();}
>
> Does C++/CLI automatically class GC::SuppressFinalize(this), or is
> there a chance of double free here? As well, there's nothing
> stopping a non-C++ client from calling Dispose more than once, so I
> think it is important to add logic to avoid the double free.

You can be right. The example is incomplete, but thanks for the hint (for
Dirk in particular). Have to add this to my todo-list also.


Armin