Re: problem with delete - COM Discussion Boards

Roger Stoltz15-Mar-07 7:13

Roger Stoltz

15-Mar-07 7:13

Since you're deleting a pointer of base class type, it's imperative that the destructor is declared virtual. If not you'll probably get an exception.

If you have declared your destructors as virtual, I suggest you post some code that shows the destructor definitions and how your p variable is declared.

"It's supposed to be hard, otherwise anybody could do it!" - selfquote
"High speed never compensates for wrong direction!" - unknown

janadhana16-Mar-07 2:35

janadhana

16-Mar-07 2:35

I already have the base class destructor set to virtual.

Thanks

Thanks & Regards,
Dhana

Roger Stoltz16-Mar-07 3:15

Roger Stoltz

16-Mar-07 3:15

jana_dhana wrote:
I already have the base class destructor set to virtual.

Ok, so where's the code snippets I asked for? Wink | ;)

From what you have described in your first post neither prasad nor I can find anything wrong, so we're just guessing at this point.
My guess was that you could have forgotten to declare the destructor as virtual, but I also suggested that if you've already done that you should post some code. Since you haven't posted any code at least I don't have any better guess.

"It's supposed to be hard, otherwise anybody could do it!" - selfquote
"High speed never compensates for wrong direction!" - unknown

prasad_som15-Mar-07 18:38

15-Mar-07 18:38

To add to roger's suggestion,

jana_dhana wrote:
if(p)
delete p;

It is good practice to set pointer to NULL, after deletion, and no need to check pointer for NULL. It is safe to call delete on NULL pointer.
you can modify your code to,

delete p;
p = NULL;

And obviously, its needed some more code to see, to track down the problem.

Prasad
Notifier using ATL | Operator new[],delete[][^]

janadhana16-Mar-07 2:38

janadhana

16-Mar-07 2:38

Please note that in method 1 i just create the object and assign it to pointer

in method 2 i am checking that if it was already created then i dont want it now and want to create a new object and assign it to the pointer.

but in method2 when i try to delete the object which was created in method1
it causes exception of unknown type.

Thanks

Thanks & Regards,
Dhana

prasad_som16-Mar-07 2:42

How to Create the plug-in toolbar for Windows Live Messenger using VC++?

16-Mar-07 2:42

Its seems diificult to judge. But, Initialize pointer you are talking about in c'tor of your coclass. I'm sure in method2, you are deleting uninitilized pointer(which is not set to NULL).

Prasad
Notifier using ATL | Operator new[],delete[][^]

A.Venkata ramana14-Mar-07 23:48

A.Venkata ramana

14-Mar-07 23:48

Hi to All,

Could any one Help me, How to create the plug-in toolbar for windows live Messenger using vc++?

What should I do?

Advance thanks

Ramana AV

Invalid pointer exception

shivapriyak14-Mar-07 19:52

shivapriyak

14-Mar-07 19:52

Hi,
I have an existing COM which is up and running...now i have added another method in the COM but when i am trying to call that method from the client application I am getting an exception:
0x80004003:Invalid Pointer

Both my COM and the client application are written in VC++
Can anyone help me out with this??

Thnx,

Priya

prasad_som14-Mar-07 20:01

14-Mar-07 20:01

When you modify interface, you need to change either major version number or minor version number. Have you done that ?
Refer this[^] for more inof.

Prasad
Notifier using ATL | Operator new[],delete[][^]

shivapriyak14-Mar-07 21:29

shivapriyak

14-Mar-07 21:29

Hi,
I haven't changed any version. So can u tell me how to change the version??
I am new to COM and so i donno this...

Thanks

Priya

prasad_som14-Mar-07 21:36

14-Mar-07 21:36

In your .idl file , there must be block like this,

[
	uuid(2EF0C5B1-0E6D-4793-8897-51BC19A18F58),
	version(1.0),//this is version number
	helpstring("Project name 1.0 Type Library")
]

Modify this to,

[
	uuid(2EF0C5B1-0E6D-4793-8897-51BC19A18F58),
	version(1.1),//this is version number
	helpstring("Project name 1.1 Type Library")
]

Prasad
Notifier using ATL | Operator new[],delete[][^]

shivapriyak14-Mar-07 21:51

shivapriyak

14-Mar-07 21:51

Hi,
Thnx for the help..I tried it out but it didn't work!!
I changed the version number and the helpstring and tried attaching that COM .tlb file again..but still the same error is coming..
Any other solution??

Thnx

Priya.

prasad_som14-Mar-07 22:36

Re: What does "THIS_" mean?

14-Mar-07 22:36

I dont see any ohter problem. See, using your component, in other clients like VB.
I'm feeling, some how , your added method is not getting recognized.

Prasad
Notifier using ATL | Operator new[],delete[][^]

What does "THIS_" mean?

[d3m0n]14-Mar-07 5:26

[d3m0n]

14-Mar-07 5:26

Hi The COM interfaces in my application derive from IUnknown. But some interface functions are declared using the "THIS_" parameter, some with "THIS" and some with none. For example:

1. STDMETHOD(DoBlah1) (THIS_ UINT uNum) PURE;
2. STDMETHOD(DoBlah2) (UINT uNum) PURE;

3. STDMETHOD(DoBlah3) (THIS_) PURE;
4. STDMETHOD(DoBlah4) (THIS) PURE;
5. STDMETHOD(DoBlah5) () PURE;

I would like to know whether the "THIS_" or "THIS" keywords are necessary, and what would be the difference between these functions.

(I couldn't find the definitions of THIS or THIS_ in the VC browser or on the net... Unsure | :~

)

Cheers
d3m0n

Roger Stoltz14-Mar-07 6:55

Roger Stoltz

14-Mar-07 6:55

THIS_, THIS and PURE are macros defined in basetyps.h and objbase.h. They are used for portability reasons with plain C, thus the code will compile with a C-compiler if written correctly.

Have a look at Jeff Glatt's article serie about COM in plain C. You'll find the first article here[^].
You'll find the other parts, 2 to 8, in various chapters below the COM section here[^].

"It's supposed to be hard, otherwise anybody could do it!" - selfquote
"High speed never compensates for wrong direction!" - unknown

Re: What does "THIS_" mean?

[d3m0n]14-Mar-07 13:01

[d3m0n]

14-Mar-07 13:01

Thank you very much Roger, that is a perfect answer for me. Rose | [Rose]

I'll ensure that all my interfaces contain the THIS_ and THIS macros.

Cheers
d3m0n

Capicom dll- require clarification urgently

anufabian14-Mar-07 0:30

anufabian

14-Mar-07 0:30

I am using capicom and doing the encryption , the algorithm is 3DES. I am encryting a value and using this value I am doing an encryted login to a site.

I have set the source of the iframe as this url , in which the encrypted value is passed as a query string.

My problem is , I am able to view the page some times and other insatnces I get a "Page Cannot be displayed " message i.e. Error 404 .

Is this due to some problem in encrytion or decrytion. Or is it due to something that is related a .Net while doin an encrypted login.

I am not sure how to trace at who's end the problem is.

Have any body faced a problem like this, please help

Thanks in advance

A COM'S Events Problem

huangdingjun13-Mar-07 20:53

huangdingjun

13-Mar-07 20:53

在一个ＣＯＭ事件中，有这么个事件接口
dispinterface _IATLDiceObjEvents
{
properties:
methods:
[id(1)] void Test([in]double x, [in] double y);
};

然而在我的事件接收代码中，得到的x,y值是不是原来激发时所传递的．
接收事件的是一个ATL的对话框类，代码如下：
// MyDialog.h : Declaration of the CMyDialog

#ifndef __MYDIALOG_H_
#define __MYDIALOG_H_

#include "resource.h" // main symbols
#include <atlhost.h>

#import "E:\AtlOcx\Debug\AtlOcx.dll" raw_interfaces_only, raw_native_types, no_namespace, named_guids

/////////////////////////////////////////////////////////////////////////////
// CMyDialog
class CMyDialog :
public CAxDialogImpl<cmydialog>,
public IDispEventImpl<idc_atldiceobj1, cmydialog="">//,&DIID__IATLDiceObjEvents,&LIBID_ATLOCXLib, 1, 0>
{
public:
CMyDialog()
{
m_pATLDiceObj = NULL;
}

~CMyDialog()
{
}

enum { IDD = IDD_MYDIALOG };

BEGIN_MSG_MAP(CMyDialog)
MESSAGE_HANDLER(WM_LBUTTONDBLCLK, OnLButtonDblClk)
MESSAGE_HANDLER(WM_INITDIALOG, OnInitDialog)
COMMAND_ID_HANDLER(IDCANCEL, OnCancel)
COMMAND_HANDLER(IDC_OPEN_BUTTON, BN_CLICKED, OnClickedOpen_button)
MESSAGE_HANDLER(WM_CLOSE, OnClose)
END_MSG_MAP()
// Handler prototypes:
// LRESULT MessageHandler(UINT uMsg, WPARAM wParam, LPARAM lParam, BOOL& bHandled);
// LRESULT CommandHandler(WORD wNotifyCode, WORD wID, HWND hWndCtl, BOOL& bHandled);
// LRESULT NotifyHandler(int idCtrl, LPNMHDR pnmh, BOOL& bHandled);
LRESULT OnLButtonDblClk(UINT uMsg, WPARAM wParam, LPARAM lParam, BOOL& bHandled)
{
return 0;
}
LRESULT OnInitDialog(UINT uMsg, WPARAM wParam, LPARAM lParam, BOOL& bHandled)
{
AtlAdviseSinkMap(this, TRUE);// 增加监听连接
return 1; // Let the system set the focus
}
LRESULT OnCancel(WORD wNotifyCode, WORD wID, HWND hWndCtl, BOOL& bHandled)
{
AtlAdviseSinkMap(this, FALSE);
EndDialog(wID);
return 0;
}
public :

BEGIN_SINK_MAP(CMyDialog)
//Make sure the Event Handlers have __stdcall calling convention
SINK_ENTRY(IDC_ATLDICEOBJ1, 0x1, OnTest)
END_SINK_MAP()
HRESULT __stdcall OnTest(DOUBLE x, DOUBLE y)
{
CComVariant varResult;
// TODO : Add Code for event handler.
// here x,y is changed．

return varResult.scode;
}
};

#endif //__MYDIALOG_H_

请问为什么在事件触发中，参数类型为'double'的数据会发生变化?

Thanks in advance!

How to Install .dll files in the Registry?

senthil_rajesh_kavin12-Mar-07 19:12

senthil_rajesh_kavin

12-Mar-07 19:12

Hai,
Plz anyone give the solution for ,How to install .dll files in the windows Registry using Regsvr32 ?
Please Clearly state the steps for installation.

Re: How to Install .dll files in the Registry?

prasad_som12-Mar-07 19:17