Re: IUnknown interface - C / C++ / MFC Discussion Boards

Re: "Mark Salsbery", "cPallini" : Answer me ...

Hamid_RT14-Sep-08 0:17

Hamid_RT

14-Sep-08 0:17

Does it necessary or no? Laugh | :laugh:

Re: "Mark Salsbery", "cPallini" : Answer me ...

CPallini14-Sep-08 0:35

CPallini

14-Sep-08 0:35

It's polite.
Smile | :)

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Re: "Mark Salsbery", "cPallini" : Answer me ...

Hamid_RT14-Sep-08 0:41

Hamid_RT

14-Sep-08 0:41

Title of his message is "Mark Salsbery", "cPallini" : PLEASE but I dont know he wants to serach about messages of Mark Salsbery and cPallini or he needs help of them? Wink | ;)

Re: "Mark Salsbery", "cPallini" : Answer me ...

Perspx14-Sep-08 0:46

Perspx

14-Sep-08 0:46

He modified the title. It was originally "Mark Salsbery", "cPallini" : Answer me ...

Regards,
--Perspx

Don't trust a computer you can't throw out a window

-- Steve Wozniak

Re: "Mark Salsbery", "cPallini" : Answer me ...

Joseph Marzbani13-Sep-08 23:51

Joseph Marzbani

13-Sep-08 23:51

I really apologise for what I said and promise It won't happen again ...
I thank all you cool guys for your helps by now ...

IUnknown interface

George_George13-Sep-08 21:22

George_George

13-Sep-08 21:22

Hello everyone,

I am confused about one simple concept of IUnknown when reading some code,

1. Every coclass component must implement IUnknown, but not a must that every interface (which the coclass component implements) must implement IUnknown;

2. Every interface of every coclass component must implement IUnknown.

Which one is correct?

thanks in advance,
George

Re: IUnknown interface

CPallini13-Sep-08 22:10

CPallini

13-Sep-08 22:10

Every interface of every COM component must implement IUnknown since every interface is required to support interface navigation via QueryInterface.
Smile | :)

Re: IUnknown interface

George_George13-Sep-08 23:09

George_George

13-Sep-08 23:09

Thanks CPallini,

Cool! I think your option is you agree with my option 2. Then another question, suppose my component implements interface IX and IY, and both IX and IY will implement IUnknown, so will there be diamond problem?

regards,
George

Re: IUnknown interface

CPallini13-Sep-08 23:45

CPallini

13-Sep-08 23:45

George_George wrote:
I think your option is you agree with my option 2.

Yes.

George_George wrote:
Then another question, suppose my component implements interface IX and IY, and both IX and IY will implement IUnknown, so will there be diamond problem?

Nope (a coclass is not a C++ class).
Smile | :)

Re: IUnknown interface

George_George14-Sep-08 0:09

George_George

14-Sep-08 0:09

Thanks CPallini,

I think for the diamond issue I mentioned, you mean writing some code like this in my sample? The normal solution is providing one common implementation of AddRef/Release/QueryInterface in CFoo, so there is no diamond problem?

CFoo:IX, IY {// provide one common implementation of AddRef/Release/QueryInterface in CFoo, so there is no diamond problem?}

IX:IUnknown{}

IY:IUnknown{}

IUnknown{}

regards,
George

Re: IUnknown interface

Hamid_RT14-Sep-08 0:16

Hamid_RT

14-Sep-08 0:16

See here[^].

Re: IUnknown interface

George_George14-Sep-08 0:19

George_George

14-Sep-08 0:19

Thanks Hamid,

Looks like different from what CPallini said -- CPallini said every interface must implement IUnknown, but the wiki page mentioned every component must implement IUnknown -- "COM objects must minimally implement this interface"? I am confused.

Could you clarify please? Smile | :)

regards,
George

Re: IUnknown interface

Hamid_RT14-Sep-08 0:33

Hamid_RT

14-Sep-08 0:33

I think here[^] and here[^] are good articles for you.

Re: IUnknown interface

George_George14-Sep-08 1:52

George_George

14-Sep-08 1:52

Thanks Hamid,

What is your conclusion of my orignial question? You agree with my point 1 of point 2?

regards,
George

Unusual memory leak ( code attached )

Yanshof13-Sep-08 20:12

Yanshof

13-Sep-08 20:12

I have some memory leak in my code.
In my application i have some method that called every 5 seconds - and i found that my memory leak is in this method.
The leak increase the memory for 4kb every 5-10 seconds.

Attached the part of the code that i found that causing the memory leak.

void foo(const VARIANT FAR& Var1, const VARIANT FAR& Var2, const VARIANT FAR& Var3)
{
	COleSafeArray SafeV1, SafeV2, SafeV3;
	SafeV1 = Var1;
	SafeV2 = Var2;
	SafeV3 = Var3;
		
	int iNumObjs = SafeV1.GetOneDimSize();
	COleVariant vV1, vV2, vV3;
	for ( long i = 0 ; i < iNumObjs ; i++ )
	{
		CString  TempV1,Value;

		SafeV1.GetElement(&i, &vV1);
		TempV1 = vV1.bstrVal;
		
		SafeV2.GetElement(&i, &vV2);
		
		SafeV3.GetElement(&i, &vV3);
		Value = vV3.bstrVal;	
	}
}

Re: Unusual memory leak ( code attached )

CPallini13-Sep-08 23:19

CPallini

13-Sep-08 23:19

Try to change from:

COleVariant vV1, vV2, vV3;		
for ( long i = 0 ; i &lt; iNumObjs ; i++ )	
{
    CString  TempV1,Value;

to:

for ( long i = 0 ; i < iNumObjs ; i++ )	
{
  COleVariant vV1, vV2, vV3;		
  CString  TempV1,Value;

Re: Unusual memory leak ( code attached )

Yanshof13-Sep-08 23:32

Yanshof

13-Sep-08 23:32

Aleady try this and this is not helping to my mem leak ... Frown | :(

Re: Unusual memory leak ( code attached )

CPallini13-Sep-08 23:58

CPallini

13-Sep-08 23:58

Strange, it should.
Smile | :)

Re: Unusual memory leak ( code attached )

Yanshof14-Sep-08 0:04

Yanshof

14-Sep-08 0:04

I know that its strange Frown | :(

Re: Unusual memory leak ( code attached )

CPallini14-Sep-08 0:32

CPallini

14-Sep-08 0:32

I mean the origina posted code was wrong.
On the other hand, if you're still experiencing memory leaks, probably there's a problem elsewhere. Does the dump of the memory block give you any insight?
Smile | :)

Re: Unusual memory leak ( code attached )

Yanshof14-Sep-08 0:35

Yanshof

14-Sep-08 0:35

The place of the leak is there - i check it be return in the first line of the method - and its does not give me the leak.
the dump mem deos not help.

Re: Unusual memory leak ( code attached )

CPallini14-Sep-08 4:09

CPallini

14-Sep-08 4:09

Why do you assume that all fo the three input arrays have the same size?
What do the arrays contain (i.e. what are the actual parameters of the call)?
Smile | :)

AfxOleInit called OleInitialize inside, but no AfxOleUninit

followait13-Sep-08 17:32

followait

13-Sep-08 17:32

So where is the correspond OleUninitialize?

system

Re: AfxOleInit called OleInitialize inside, but no AfxOleUninit

CPallini14-Sep-08 6:41

CPallini

14-Sep-08 6:41

Inside AfxPostQuitMessage, called for instance in the WM_NCDESTROY message handler.
Smile | :)

warning C4244 ... conversion from 'int' to 'char', possible loss of data

FrankMookie13-Sep-08 16:04

FrankMookie

13-Sep-08 16:04

Hi.
I'm getting this warning in my project:
warning C4244: '=' : conversion from 'int' to 'char', possible loss of data

This is the code:

(...)
char resp;

while(op_back!=2)
{
       (...)
	if(A !=0)
	{
	do
	{
		(...)
		cout<<"Do you want to modify this object? [Y/N]  ";
		fflush(stdin); cin>>resp;
		resp=toupper(resp);	
        }while(!(resp=='Y' || resp=='N'));
		if(resp=='Y')
		{
                (...)

Is there an easy way to resolve this warning?

And another warning:
warning C4310: cast truncates constant value

gotoxy(0,1);cout<<char(218);

Thank you!
Thank you

"Failure is always an option."

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