C / C++ / MFC Discussion Boards

Re: My DllMain is not getting invoked.

Peter Molnar11-Dec-03 14:40

Peter Molnar

11-Dec-03 14:40

I have created a small project which contains 4 lines of code:

#include <windows.h>
BOOL DllMain(HINSTANCE , DWORD , LPVOID ) 
{   
	::MessageBox(NULL,"test","Caption",MB_OK);      
	return TRUE;
}

and call it

HINSTANCE hInstance = LoadLibrary("pathto.dll");

works just fine.
Try the same. What is hInstance when you debug?

Peter Molnar

SUCCESS!!!

Matthew Busche12-Dec-03 18:08

Matthew Busche

12-Dec-03 18:08

Much thanks to Peter Molnar for mailing me a completely trivial DevStudio project containing a DllMain() that got properly invoked. What I was missing (and what I had never seen documented) was the APIENTRY declaration for the DLL entry point function. The DllMain must be declared like this:

BOOL APIENTRY DllMain(HINSTANCE , DWORD , LPVOID )

Once those 8 pesky characters were added, it worked great.

Also, for those who care, this works independently of the application type (i.e., works for both console apps and windows apps) and (as Peter said in an earlier message on this thread) works independently of how the library is loaded. (I.e., you can use either load-time dynamic linking or run-time dynamic linking.)

Matt

Re: My DllMain is not getting invoked.

Mike Dimmick12-Dec-03 2:03

Mike Dimmick

12-Dec-03 2:03

If this is VC6: in the Link tab, select the Output category, and ensure that Entry Point Symbol is either blank or set to _DllMainCRTStartup. You should also check that the /NOENTRY switch is not specified.

Both of you: be careful with your dependencies. The only routines you can guarantee will be initialised before your entry point is called are those implemented by KERNEL32.DLL. You should also be able to call C library functions if you're linking with the C run-time.

Floating CDialogBar

Jon Sagara11-Dec-03 11:38

Jon Sagara

11-Dec-03 11:38

I have a floating CDialogBar whose caption I can't seem to change with SetWindowText. Does anyone know how to change the caption text?

Thx,

Jon Sagara
Vegetarianism is unhealthy. Humans need protein, and lots of it. Put down those sprouts and pick up a T-bone!
-- Michael Moore

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Re: Floating CDialogBar

Jon Sagara11-Dec-03 19:46

Jon Sagara

11-Dec-03 19:46

FYI, I found this on that *other* developer site:

http://www.codeguru.com/mfc/comments/40598.shtml[^]

Jon Sagara
Vegetarianism is unhealthy. Humans need protein, and lots of it. Put down those sprouts and pick up a T-bone!
-- Michael Moore

Latest Article: Breadcrumbs in ASP.NET

Help?

Anonymous11-Dec-03 11:34

Anonymous

11-Dec-03 11:34

I am having a difficult time with the following project:

http://www.cse.psu.edu/~cg103/NewHW/proj3.pdf
http://www.cse.psu.edu/~cg103/NewHW/alice.txt

Can anyone toss me a hint (pseudocode would be great!).

Re: Help?

Terry O'Nolley11-Dec-03 15:23

Terry O'Nolley

11-Dec-03 15:23

Anonymous wrote:
I am having a difficult time with the following project:

Are you having a difficult time, or have you not started and are running out of time?

The encyption algorithm has been given to you:

"For a given message, we substitute each lowercase character to the other character
whose ASCII code is less than 6."

This tells you that you can ignore any characters that aren't lower case letters (ie you only need to encrypt chars whose ascii values are between 97 and 122, inclusive)

So, a high-level step-by-step process list could be:

1) Get next character
2) Is it a lower case letter?
No: Store it as is
Yes: subtract 6 and then store it
3) Is it the last character?
No: GOTO #1
Yes: EXIT

In pseudocode:

OPEN input file
LOOP
GET character from file

IF character is lower case letter
subtract 6 from it

STORE character

IF end of file
EXIT LOOP
END LOOP

CLOSE input file

OPEN output file

LOOP
GET encypted character

WRITE encrypted character

IF end of encypted characters
EXIT LOOP
END LOOP

CLOSE output file

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DLL question

Diarrhio11-Dec-03 11:18

Diarrhio

11-Dec-03 11:18

I am creating a dll (non-MFC). I am getting linker errors from the .exe that is trying to link with it.

The linker is complaining about the static class variables, unresolved external symbol. How am I to "decorate" them? I've tried using __declspec(dllexport) but haven't had much luck.

Thanks

Re: DLL question

Diarrhio11-Dec-03 12:52

Diarrhio

11-Dec-03 12:52

Well, I finally got it figured out, in case anybody is curious.

The compiler directive should be dllexport when compiling the dll, and dllimport when compiling the exe.

#ifdef _DLL_
#define DLL_GLOBAL __declspec(dllexport)
#else
#define DLL_GLOBAL __declspec(dllimport)
#endif

might be a dumb question...

l a u r e n11-Dec-03 11:07

l a u r e n

11-Dec-03 11:07

if i calloc() a buffer and write data into it and then later copy other data into it that is shorter than the original data (and zero terminated) will the entire original buffer be freed properly when i call free() on it?

"there is no spoon"
biz stuff about me

Re: might be a dumb question...

Jörgen Sigvardsson11-Dec-03 11:11

Jörgen Sigvardsson

11-Dec-03 11:11

Yes. calloc(num, size) is just shorthand for memset(malloc(num * size), 0, num * size).

--
20 eyes in my head, they're all the same![^]

Re: might be a dumb question...

l a u r e n11-Dec-03 11:19

l a u r e n

11-Dec-03 11:19

thnx guys
doh i feel dumb now
Roll eyes | :rolleyes:

"there is no spoon"
biz stuff about me

Re: might be a dumb question...

Matthew Busche11-Dec-03 11:17

Matthew Busche

11-Dec-03 11:17

That is my understanding. It is also my understanding that night will be followed by day in the coming hours. I could be mistaken about one or the other or both, but I'm fairly certain about both.

Matt

resource DLL

alex.barylski11-Dec-03 10:03

alex.barylski

11-Dec-03 10:03

Edit: I'm not using MFC BTW

I made a blank DLL project, copied my resources over to the DLL compiled, everything is fine...

I then loaded my resource DLL inside my app...it's load fine...but nothing is showing...obviously my resources need special attention when stored in a DLL...

What steps do I have to take to make sure my Dialogs, Menus, etc...load...and are shown...?

Thanks Smile | :)

The word of the day is legs, let's go back to my house and spread the word Poke tongue | ;-P

Re: resource DLL

Jörgen Sigvardsson11-Dec-03 11:08

Jörgen Sigvardsson

11-Dec-03 11:08

If you're using Win32, then I guess you just pass the handle to the loaded resource dll to CreateDialog() et al.

--
20 eyes in my head, they're all the same![^]

Re: resource DLL

Michael Dunn11-Dec-03 14:46

Michael Dunn

11-Dec-03 14:46

Check that you are using the right HINSTANCE (that of the resource-only DLL) in all your resource-related API calls.

--Mike--
Ericahist | CP SearchBar v2.0.2 | Homepage | RightClick-Encrypt | 1ClickPicGrabber
If my rhyme was a drug, I'd sell it by the gram.

Re: resource DLL

alex.barylski11-Dec-03 15:09

alex.barylski

11-Dec-03 15:09

Thats what the problem was... Blush | :O

The word of the day is legs, let's go back to my house and spread the word Poke tongue | ;-P

CStatusbar and an afxMsg question

ns11-Dec-03 9:06

11-Dec-03 9:06

I see this in a sample on CP for a CStatusbar derived class. But I cant figure out how to get the classwizard to add the afx_msg UINT OnNcHitTest(CPoint point) handler . This class CTextualStatusBar doesnt show up in the class wizard. SO I thought maybe if I right click in the left panel classview window on this class and get "Add windows message handler" I migtht be able to do it that way. But for this class, that menu item isnt in the context menu. Yet this handler is in the afx area and its grey which means the wizard generated it. AM I overlooking something obvious?
Thanks.
ns

class CTextualStatusBar : public CStatusBar
{
public:
	CTextualStatusBar();

public:
	virtual ~CTextualStatusBar();

	// Generated message map functions
protected:
	//{{AFX_MSG(CTextualStatusBar)
	afx_msg int OnCreate(LPCREATESTRUCT lpCreateStruct);
	afx_msg void OnDestroy();
	afx_msg UINT OnNcHitTest(CPoint point);
	//}}AFX_MSG
	DECLARE_MESSAGE_MAP()
};

Re: CStatusbar and an afxMsg question

Ravi Bhavnani11-Dec-03 9:35

Ravi Bhavnani

11-Dec-03 9:35

I would just add the handler manually.

ClassWizard can behave in a severely brain damaged manner, especially when the class files don't exist in the project's root folder. Frown | :(

/ravi

Let's put "civil" back in "civilization"
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Re: CStatusbar and an afxMsg question

ns11-Dec-03 9:41

11-Dec-03 9:41

okay. Thanks.

Windows app command line args

act_x11-Dec-03 8:19

act_x

11-Dec-03 8:19

I need to pass Command line arguments to my MFC wizard created app and store the values in a local variable .

Where can i trap these values in code ?

I need something like
main(int argc ,char *argv[])

Please help

Re: Windows app command line args

David Crow11-Dec-03 9:00

David Crow

11-Dec-03 9:00

See CWinApp::m_lpCmdLine.

Five birds are sitting on a fence.
Three of them decide to fly off.
How many are left?

Re: Windows app command line args

Michael Dunn11-Dec-03 9:48

Michael Dunn

11-Dec-03 9:48

The CRT also sets up the global variables __argv and __argc for you, which mirror argc and argv that you get in a console mode app.

--Mike--
Ericahist | CP SearchBar v2.0.2 | Homepage | RightClick-Encrypt | 1ClickPicGrabber
Actual sign at the laundromat I go to: "No tinting or dying."

Re: Windows app command line args

act_x11-Dec-03 9:50

act_x

11-Dec-03 9:50

CRT ?

Engineering is the effort !

Re: Windows app command line args

Jörgen Sigvardsson11-Dec-03 11:12

Jörgen Sigvardsson

11-Dec-03 11:12

C Run Time. printf et al. Smile | :)

--
20 eyes in my head, they're all the same![^]

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