Console Output for a Windows App - C / C++ / MFC Discussion Boards

Re: Please !!! help me ! please ! HELP !!!

9-Jul-01 10:11

Generally, you get an error like that because you have set a limitation on the number associated with the edit control. For instance, if you code the following in your DoDataExchange() function:

DDV_MinMaxInt( pDX /*CDataExchange Object*/,
m_iNumber /*member of this class*/,
50, /*minimum accepted value*/
999 /*maximum accepted value*/ );

You will get an error when your dialog is initialized if the data m_iNumber is not in the valid range.

What is it? -- Forward Class Declaration

C~~MFC6.0~~VS.NETUser9-Jul-01 7:11

C~~MFC6.0~~VS.NETUser

9-Jul-01 7:11

I have seen search in MFC header file I have found to be call something like "Forward Class Declaration".

Here is an example of what I found... (Class Names Changed)
class CANormalCPPClass
{
class CAForwardableClassDeclaration; /*forward declaration of CAForwardableClassDeclaration*/
...
}

What going on in a class like this and how usefull is Forward Class Declaration?

Re: What is it? -- Forward Class Declaration

Tomasz Sowinski9-Jul-01 7:37

Tomasz Sowinski

9-Jul-01 7:37

The forward declaration tells the compiler that some name is used for a class. You could #include appropriate header, but this would (a) make compile longer and (b) introduce dependencies between two headers. You can't create variables of the forwared type, unless you provide full type definition, usually via #include. You can create pointers and references.

class CForward;

class CTest
{
// ...
CForward *m_Forward; // OK
CForward &m_rForward; // OK
CForward m_Forward; // won't compile

void Test1(CForward *pForward); // OK
void Test2(CForward &rForward); // OK
void Test3(CForward forward); // OK
};

Tomasz Sowinski -- http://www.shooltz.com

Re: What is it? -- Forward Class Declaration

9-Jul-01 7:46

A Forward Declaration is pretty much exactly what it sounds like. You declare a class before you actually define it. It is very useful for certain dependency issues which often arise in C++.

For example:

class CDefinedLater; // Defined later in the object list

class CDefinedNow{ // being defined now.
{
CDefinedLater* m_pdefinedlater; // Must be instantiated in the implentation of CDefinedNow.
};

In this way you do not have to include the header where CDefinedLater is defined in this header file, but you also cannot instatiate/construct CDefinedLater here. Doing so would make everything that is dependent upon this class, likewise dependent upon the CDefinedLater module, which can get messy.

i.e.
CDefinedLater m_definedlater;

This keeps your dependency relationships much simpler. I know a lot of people who swear by it. I also know alot of people who overuse it, instead of haveing well thought out dependencies in their class heirarchy.

Re: What is it? -- Forward Class Declaration

Malcolm McMahon13-Jul-01 2:50

Malcolm McMahon

13-Jul-01 2:50

More to the point, you might have two classes each of which contains pointers to the other, in which case forward class declarations are unavoidable.

Re: What is it? -- Forward Class Declaration

C~~MFC6.0~~VS.NETUser9-Jul-01 17:38

C~~MFC6.0~~VS.NETUser

9-Jul-01 17:38

Thank you for the replys.

Re: What is it? -- Forward Class Declaration

C~~MFC6.0~~VS.NETUser9-Jul-01 17:38

C~~MFC6.0~~VS.NETUser

9-Jul-01 17:38

Thank you for the replys.

Console Output for a Windows App

Jason Callis9-Jul-01 5:34

Jason Callis

9-Jul-01 5:34

I have currently converted an SDI MFC app to run non-interactively from the command line
to be used in a MakeFile. The problem is returning error messages and reports back
to the user. Does anyone know of a way to use printf (or any other output function) from
a windows app to the console that executed it?

Thanks for all your help.

Please drop me a line if you can help: JasonC@Codemasters.com

Re: Console Output for a Windows App

Tomasz Sowinski9-Jul-01 8:20

Tomasz Sowinski

9-Jul-01 8:20

It's possible to open new console window and printf() into it (see KB article Q105305 for details). I think you can't use parent process console from a GUI program - the easiest way to solve your problem would be moving the non-interactive parts into console app. If you need to share this functionality with GUI app, create a DLL.

Tomasz Sowinski -- http://www.shooltz.com

Re: Console Output for a Windows App

Carlos Antollini9-Jul-01 8:44

Carlos Antollini

9-Jul-01 8:44

Look in the MSDN in Platform SDK/Base Services/Files and I/O/Consoles and Character Mode Support.
You will find a lot of functions like WriteConsole() etc.

Good Luck.
Big Grin | :-D

Carlos Antollini.

Howto find where user clicks?

MolleX9-Jul-01 4:41

MolleX

9-Jul-01 4:41

Hi,

I have a CFormView that contains a CTreeCtrl and a CHeaderCtrl. Everything works fine and the tree is divided in different columns but how do I find out what row and column a user has clicked on?

Cheers

Re: Howto find where user clicks?

9-Jul-01 5:58

Do you mean CTreeCtrl or CListCtrl? If you have a CTreeCtrl in columns, I would like to know how you did it.

Re: Howto find where user clicks?

MolleX10-Jul-01 1:14

MolleX

10-Jul-01 1:14

I have a CTreeCtrl in columns, there is very good examples on this site to achieve that.
I have found out what column the user clicks in but I can't find the row of the click.

Retreiving processor serial number

MoZ9-Jul-01 3:29

MoZ

9-Jul-01 3:29

Hi All,
Is there any function or API to retreive the processor serial number.
Confused | :confused:

Thanks

Moz
Tunis - Tunisia

Re: Retreiving processor serial number

Pavlos Touboulidis9-Jul-01 10:25

Pavlos Touboulidis

9-Jul-01 10:25

I don't think there's an API function for that, but even if there was, I wouldn't tell you Poke tongue | ;-P

Seriously, this is probably done with (inline) assembly. I suppose you emit an instruction to the CPU and you get the result in some registers. I don't know how though. I guess it's another extension of the CPUID instruction. If you use it, you should put the code inside try/catch blocks, because CPUs that don't support the instruction will produce an invalid opcode exception.
Btw, why would you do that?

Re: Retreiving processor serial number

orcun colak10-Jul-01 8:04

orcun colak

10-Jul-01 8:04

I was also wondering the same thing. I remember seeing an example at www.codeguru.com for getting cpu properties using inline assembly but since i do not know assembly very well i could not understand it.

Orcun Colak
orcuncolak@yahoo.com

_declspec(property) Question

Philip Patrick9-Jul-01 2:32

Philip Patrick

9-Jul-01 2:32

Did somebody used _declspec(property) attribute?
If yes, please tell me how!
I have such code:
[code]
class CSome{
inline long GetMicroSeconds() const
{
return m_nMicroSecs;
}
_declspec(property(put=SetMicroSeconds, get=GetMicroSeconds)) long m_nMicroSecs;

};
[/code]

And get an error "Stack Overflow". I understand why, but don't understand so how to use this attribute? Confused | :confused:

Well for now it's working with assembler inside, but i don't want to use assembler. So if somebody knows the right way, please tell me.
Thanx

Philip Patrick

Re: _declspec(property) Question

coder84729-Jul-01 2:42

coder8472

9-Jul-01 2:42

You also have to declare a member variable to store the value, and then return the member variable!

But I recomend not to use _declspec(property), because the code is harder to maintain, and it also confuses people...

And I think in Visual Studio .NET you'll get a warning or an error!

maXallion
"Look for bugs, I hate bugs!" - Warden, The Mummy
www.maxallion.de - coded evil & more

Re: _declspec(property) Question

Philip Patrick9-Jul-01 3:03

Philip Patrick

9-Jul-01 3:03

First of all - Thanx. Smile | :)

Yeah you've right when say not to use it. I don't want! But i have to. It's a part of low-level modules of my company (where i work) and everybody uses this public member. But I have to keep it not bigger than 999999 (micro). So instead of doing this variable protected and changing all code, i do it "property". That's all.
Thanx again

Philip Patrick

Re: _declspec(property) Question

Tomasz Sowinski9-Jul-01 2:44

Tomasz Sowinski

9-Jul-01 2:44

You're getting into infinite resursion - any attempt to read m_nMicroSecs is redirected to GetMicroSeconds; that's what __declspec(property) does. You need to create separate data member to hold the microseconds. There's an article dealing with this on CodeProject.

Tomasz Sowinski -- http://www.shooltz.com

Thanks a lot !

9-Jul-01 2:17

SetCapture problem in modal dialog

Christian Graus9-Jul-01 2:11

Christian Graus

9-Jul-01 2:11

I have written us a colour picker to replace the scabby Windows one, and especially with GDI+, allow us to enter alpha as well. My managet wants to be able to select colours from anywhere on the screen by clicking on them. Rather than make the dialog modeless, I decided to be cunning, and call SetCapture and then just check if I have clicked outside the dialog. I call SetCapture in OnInitDialog, and then in OnLButtonDOwn I do this:

CRect rc;
GetWindowRect(&rc);
CPoint pt = point;
ClientToScreen(&pt);
if (!rc.PtInRect(pt))
{
    CWindowDC window(NULL);
    COLORREF rgb = window.GetPixel(pt);
    UpdateData();
    m_Red = GetRValue(rgb);
    m_Green = GetGValue(rgb);
    m_Blue = GetBValue(rgb);
    UpdateData(false);
    ReleaseCapture();
    SetCapture();
    Invalidate(false);
    return;
}

I've added releasecapture and setcapture to try and solve my problem, which is this. This all works great the first time I do it, after that it won't work at all. Clicking in the dialog works, of course, but I did a debug with a breakpoint set, and OnLButton down is not called again after time if I click outside the dialog. How can I keep the Capture for as long as the dialog is running ? Do I need to run a timer ? Why doesn't it work in the function as I wrote it ? Where's that piece of rope when I need it ?

Christian

#include "std_disclaimer.h"

People who love sausage and respect the law should never watch either one being made.

The things that come to those who wait are usually the things left by those who got there first.

Re: SetCapture problem in modal dialog

Tomasz Sowinski9-Jul-01 2:26

Tomasz Sowinski

9-Jul-01 2:26

Where's that piece of rope when I need it ?

Here's the rope: "Mouse capture is also affected by the Windows 95 and Windows NT localized input queues.... If the mouse is captured while the mouse button is up, the window receives mouse input only as long as the mouse is over that window or another window created by the same thread."
".

From C++ QA by Paul Dilascia, MSJ, Dec'98.

Cheers,

Tomasz Sowinski -- http://www.shooltz.com

Re: SetCapture problem in modal dialog

Christian Graus9-Jul-01 12:17

Christian Graus

9-Jul-01 12:17

Thanks.

Christian

#include "std_disclaimer.h"

People who love sausage and respect the law should never watch either one being made.

The things that come to those who wait are usually the things left by those who got there first.

Menu's

vijayaramaraju9-Jul-01 1:11

vijayaramaraju

9-Jul-01 1:11

How do we remove a popup menu I'm unable to get its Menu Id

thanks in Advance Rose | [Rose]

vijay

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