Re: Visual C++ static member initialization - C / C++ / MFC Discussion Boards

wat is the message sent out when a user logs in to a system. just like WM_ENDSESSION is send when a system shuts down, similarly wat is the message when a user logs in?

Hello,
When I have a Handle(HWND) to an Object
or in the Window I can Send a Message for It.
But if I save this Handle to a File after running
the Window again, I can't Use the saved handle to
send message to it.
is there any way to save a handle or something like
that and use it again?
Best Wushes.
Thanks.

a handle is created dynamically at runtime by windows. not a good thing to depend on. dont save the hwnd. instead, use some other means like FindWindow()

Bikram Singh

Dear all,

I'm developing an SNMP manager using WinSNMP API. While starting up the SNMP by calling the function SnmpStartup, it returns SNMPAPI_SUCCESS, but strangely the 5 output parameters are not defined after the function is executed. Is this normal? Why is this happenning? What should I do?

Regards,
Alan Lewis

It's been a while since I've done MFC and I thought there used to be a header file that you could download from CP that would do some compiler optimizing for you. Does anybody know what I'm talking about or was I thinking of something else?

Hi
Let's say I have a class A. A has a static member whose type is another class, let's call it class B. Usually in my C++ application I declare this static member at the top of A's .cpp file as follows:

B A::instanceofB(aString)

where aString is of std::string type and is the argument for B's constructor.

That works OK and I got the result I wanted. However, yesterday I use that file on a different project (it's a directshow filter project) and it seems that instanceofB is never initialized there! I tried to debug it by making B's constructor to write to a file, but when I checked, the file was never written into, it's as if B's constructor's never called at all. I did that for B's default constructor too, but with the same result. I checked in all the project settings but I couldn't find out what causes this discrepancy.

Could someone point me on what's the possible causes for this?

Thanks!

what about putting breakpoints in B's constructor? Or could you maybe declare the instanceofB inside A's constructor?. Maybe the compiler did realized that instanceofB was never used and therefore no code was generated?

modified 26-Oct-22 21:01pm.

Indrawati wrote:
Let's say I have a class A. A has a static member whose type is another class, let's call it class B. Usually in my C++ application I declare this static member at the top of A's .cpp file as follows:

B A::instanceofB(aString)

where aString is of std::string type and is the argument for B's constructor.

That works OK and I got the result I wanted. However, ... it seems that instanceofB is never initialized there!

Where/how/when is aString initialized - i hope it's before instanceofB. If not then instanceofB is initialized (at best) with an empty string.

This alone is a potential problem. This is why you try to not to polute the global pool, especially with complex objects, especially with complex constructors.
You have little control over the order globals are initialized across modules.

Basically (if i remember right) globals within a module (c/cpp file) are initialized in the order they appear. Modules have their globals initialized in an effectively undefined order. That is, you don't know if a.cpp globals are initialized before or after b.cpp globals.

You can define some control over this using the #pragma init_seg(...).
#pragma init_seg(compiler) - initialized 1st
#pragma init_seg(lib) - initialized 2nd
#pragma init_seg(user) - initialized 3rd
#pragma init_seg(my_seg) - all initialized after user, but in no other defined order

The main limits with the above are :
- you should really never use compiler unless you know what you are doing
- you can only really use init_seg() once per module and it applies to all globals that follow

This may not be the problem.

Another thing to look at is if instanceofB is being linked in - with the little info provided i can't see why it wouldn't though.

Another thing is that the file i/o state may not be initialized by the time you try to initialize instanceofB. This would prevent B::B() from writing to a file. Try using OutputDebugString().

...cmk

Save the whales - collect the whole set

Hi
aString is a global constant defined in a separate header file. Actually, I defined it as follows:

const char *const aString = "anything";

I *think* it should be no problem.

Could you please elaborate on the second potential problem (about instanceofB being linked in), since I'm not very clear about it?

Thanks!

I'm not exactly sure if I really want a custom control, but here is what I am trying to do.

Currently, we plot points on a graph. The points are stored in a vector of POINTs and are simply drawn on the screen (dc.SetPixel and dc.Ellipse). A new requirement has been added to allow users to move the points. I can either check the entire vector on a LButtonDown to see if the mouse click point matches an item in the vector or...what I am hoping is to create a new type of CCmdTarget class or CWnd so I get messages built-in. Essentially I want to create a new Point class which knows about receiving point clicks, mouse movements, etc. The idea is to move the burden of figuring out mouse clicks/moves to this new Point class.

Any help is greatly appreciated. Thanks. I figure this has been done before, but I could not find anything by doing an article search.

I cannot figure out how to get a CToolbar to show multiline strings.
I can SetButtonText, but I cannot ever get the second line to show.
This doesn't work:

<br />
m_myToolbar.GetToolBarCtrl().SetDrawTextFlags(DT_CENTER, DT_CENTER);<br />
m_myToolbar.SetButtons(NULL, 1);<br />
m_myToolbar.SetSizes(CSize(80, 80), CSize(1, 1));<br />
m_myToolbar.SetButtonText(0, "Line1\n Line2");<br />

Any help would be greatly appreciated!

Hello all gurus..
If I want to create the string that contains given digit like 3 for 3 digit in the string, how should i done it?
To clear what I'm trying to say, here is an example.
CString prefix = "pf";
int numDigit = 6;
int startNum = 1;

CString k;
k.Format("%d%d",numDigit,startNum);
k = prefix + k;

the output that I want is:
k = "pf0001"

I know I'm doing it wrong.. coz the answer wasn't the one i want it and is there any other way instead of using for or while loop, counting numberDigit.

Try this. It works.

CString prefix = "pf";<br />
int numDigit = 6;<br />
int startNum = 1;<br />
<br />
CString k;<br />
k.Format("%0*d",numDigit-prefix.GetLength(),startNum);<br />
k = prefix + k;<br />
cout << (LPCTSTR) k;

Saving one line Big Grin | :-D

CString prefix = "pf";
int numDigit = 6;
int startNum = 1;

CString k;
k.Format("%s%0*d",prefix,numDigit-prefix.GetLength(),startNum);
cout << (LPCTSTR) k;

Ivan Cachicatari
www.latindevelopers.com

Thank you both

Im trying to load a bitmap into a picture box on a dialog in MFC
can any body give me a simple example

Donald

Hello,

Does anyone know how to copy the action of the Open With... dialog option when you right click on a file in Windows Explorer?

That is, when I right click on one of my files, for example 'msg.1', Windows Explorer presents me with a dialog to choose which application I would like to open the file with.

I would like to use this action in one of my applications, but don't know how to go about it.

Any help would be greatly appreciated.

Thanks,
Murrah Boswell

Take a look at ShellExecute(...)

"No matter where you go, there your are." - Buckaroo Banzai

-pete

Hello,

In my CList ctrl, my double click handler uses ShellExecute, i.e.;

<snip>
ShellExecute(GetSafeHwnd(), NULL, GetListFilename(nIndex), NULL, NULL, SW_SHOW);
<snip>

and it works for 'known' file types, but it doesn't give me an 'Open With...' type dialog for file types that Windows Explorer doesn't know about.

Have I missed something?

Murrah Boswell

otrcomm wrote:
Have I missed something?

No I did, sorry. I just assumed that for unknown types it would display the dialog for you. You know what they say about assumptions right? Laugh | :laugh:

So after some digging here is what I found:

ShellExecute will return SE_ERR_NOASSOC for a file extension with no association. So under that condition you do this:

HINSTANCE hInst =
    ::ShellExecute(NULL, "open", "rundll32", "shell32.dll,OpenAs_RunDLL c:\\winzip.log", NULL, SW_NORMAL);

The example of course is where you tried to open the file [C:\\winzip.log]

Hope that helps

"No matter where you go, there your are." - Buckaroo Banzai

-pete

That did it!

Thanks man!

When I get the project finished that I am working on, I'll send you the code if you want it. It's a very fast search engine for files and 'text in files' for Windows. And if I get it together, I will also have it search a Win32 Squid Cache.

I already have the Squid Cache search engine working in a Unix environment (written in Perl), but now I want to get it working in the Windows environment.

Murrah Boswell

Sounds like good material for a CodeProject Article eh?

"No matter where you go, there your are." - Buckaroo Banzai

-pete

Yeah, that's where I'll post it!

I've never posted anything at CodeProject, but I guess it's high time!

Murrah

I have a memory blank ...

what's the name of the MFC shape drawing sample program ? where you can draw shapes (squares, circles, ... ) , select them, manipulate them, ...

I know about scribble, but it's not the one I want... ( or I have the wrong version ).

I need it to use as a prototype template.

Thanks.

Maximilien Lincourt
Your Head A Splode - Strong Bad

DRAWCLI, perhaps?