C / C++ / MFC Discussion Boards

mosquitooth26-Mar-06 1:49

26-Mar-06 1:49

Hi,

I've got a (probably) common problem: I want to create a several unmanged C++ DLLs in VS2005, most of them shall export functions with strings (best CString), like this:

void TestFunc1(int a, CString b);
void TestFunc2(int a, LPCTSTR b);
CString TestFunc3(int a);

All these DLLs compile and link well, but when I try to use them in my applications, I always receive a linker error (LNK2019: undefined external symbol). Obviously, this problem is related to the use of strings as arguments (or return values), because if I remove them as arguments, everything works fine...

any ideas how to solve this?

Greetings,

Peter

Re: Exporting functions with strings

Giannakakis Kostas26-Mar-06 18:35

Giannakakis Kostas

26-Mar-06 18:35

Have you created an MFC or a regular dll? MFC dlls can only be used from MFC applications. If you want to use the functions from a not-MFC application, replace CString with string.

Re: Abstract dataype

PJ Arends26-Mar-06 11:31

PJ Arends

26-Mar-06 11:31

Interesting assignment, thanks for sharing Smile | :)

You may be right
I may be crazy
-- Billy Joel --

Within you lies the power for good - Use it!

Text Formatting

Waldermort26-Mar-06 1:38

Waldermort

26-Mar-06 1:38

Hi All,

Here I am with yet another question. I am streaming text to and from a rich edit control (Not RTF format). The text in the control has all the formatting capabilities as documented by MS.

Formatting suxh as CTRL+TAB, is easy enough since a tab character is inserted into the control, then I can use STREAMOUT to get a tabified string. The problem is, I'm not sure how to deal with CTRL+E,B,U etc... Since nothing is really visible.

I want to stream out this text with the formatting, store it and recreate it again. Is this possible to do with non-RTF text, or will I have to start converting?

Class Creation Problem

vin36925-Mar-06 23:52

vin369

25-Mar-06 23:52

I need to write a wordlist class that inserts text into a binary search tree for processing. I have written a binary search tree class (below) and can input text directly into it but I am having a problem creating a wordlist class to do it. The wordlist class would also keep track of the total number of words in the list and the number of occurrences of each word. What would that class look like? Any suggestions would be greatly appreciated. Thanks.

template <class item="">
class bst_node
{
public:
// TYPEDEF
typedef Item value_type;
// CONSTRUCTOR
bst_node(
const Item& init_data = Item( ),
bst_node* init_left = NULL,
bst_node* init_right = NULL
)
{
data_field = init_data;
left_field = init_left;
right_field = init_right;
}
// MODIFICATION MEMBER FUNCTIONS
Item& data( ) { return data_field; }
bst_node* &left( ) { return left_field; }
bst_node* &right( ) { return right_field; }
void set_data(const Item& new_data) { data_field = new_data; }
void set_left(bst_node* new_left) { left_field = new_left; }
void set_right(bst_node* new_right) { right_field = new_right; }
// CONST MEMBER FUNCTIONS
const Item& data( ) const { return data_field; }
const bst_node* left( ) const { return left_field; }
const bst_node* right( ) const { return right_field; }
private:
Item data_field;
bst_node *left_field;
bst_node *right_field;
};

// NON-MEMBER FUNCTIONS for the bst_node<item>:
template <class item="">
void insert(bst_node<item>* &node_ptr, Item new_data);

template <class item="">
void print(const bst_node<item>* node_ptr);

template <class item="">
int tree_size(const bst_node<item>* node_ptr);

Re: Class Creation Problem

Stephen Hewitt26-Mar-06 12:14

Stephen Hewitt

26-Mar-06 12:14

If code is posted without formatting (indentation) it's too painful to bother with.

Steve

font of barcode

includeh1025-Mar-06 22:27

includeh10

25-Mar-06 22:27

if I use barcode fonts in my App, I think users can not use my App because they didn't install those fonts.

any free barcode fonts for download?

A nice hyper tool for optimizing your Microsoft html-help contents.
A best image tool for Windows C++ programmers, don't miss it!.

Includeh10

Beginner's Guide to DirectX

WhatNameHasn'tBeenTakenYet25-Mar-06 22:10

WhatNameHasn'tBeenTakenYet

25-Mar-06 22:10

I'm a complete beginner with C++. I'm trying to get some sample programs that use DirectX (specifically DDraw) to compile using VC++ 6, but it's making my head hurt. Is there an idiot's guide to exactly what I have to do set everything up? Or can someone help me?

So far I've:

Downloaded & installed DirectX SDK 10
Fired up VC++ 6 and:

Tools\Options\Directories - added the \SDK\Include path to the "Include files" drop down & added the \SDK\x64 and \SDK\x86 paths to the "Library files" drop down

Project\Settings\Link - added "ddraw.lib" to the "Object/Library modules"

Obviously something's wrong though, as the sample I'm trying to compile comes back with a "error C2146: syntax error : missing ';' before identifier 'lpdd'" when it gets to the first of the list of externals ("extern LPDIRECTDRAW4 lpdd; ")

I've combed the web to the best of my ability and there seems to be lots of advice on setting up Borland and DevC++ to use DirectX, but I can't find a word about Visual C - I assume I'm being stupid.

Re: Beginner's Guide to DirectX

CaesarCZ25-Mar-06 23:06

CaesarCZ

25-Mar-06 23:06

I believe DirectDraw isn't officially supported since DX8. That means you still can use it, but you won't find documentation for it (last is in DX7 SDK I believe). Make sure you're on WXP as AFAIK that's what DX10 needs.

Also, I believe LPDIRECTDRAW4 is surely older interface than necessary, try LPDIRECTDRAW7 or LPDIRECTDRAW6.

As for setting up VC 6.0: set up the prober include and library directories as you did. Move them both to the top of the list! Otherwise, it won't work (at least with DX8 I've been using). You also need to link some libs... like ddraw.lib and maybe dxguid.lib, depending on what parts of DX you use (look in the libs directory and use common sense).

I believe you should better use D3D to draw graphics. As for links, gamedev.net has some nice articles and good forums for this kind of stuff (in the forum FAQ for D3D, you can even find links to some page that has older SDK for download if you want DD documentation). A nice tutorial is at http://www.andypike.com/tutorials/ . If you just want to do 2D with D3D, look up Sprites in the SDK. Also, there are some nice tutorials in the SDK's help files.

Haven't touched DX since DX8/9, so if there's something new specifically to DX10, sorry Frown | :(

Re: Beginner's Guide to DirectX

WhatNameHasn'tBeenTakenYet25-Mar-06 23:52

WhatNameHasn'tBeenTakenYet

25-Mar-06 23:52

Thanks very much indeed - moving the includes to the top of the list did the trick. Maybe in years to come I'll understand exactly what the linker is doing, when & why....

And thanks for all the other tips. I'm only using LPDIRECTDRAW4 because I'm cutting and pasting samples from an old Andre Lamothe book (Tricks of the Windows Game Programming Gurus). I'll try updating it and thanks too for the link. Big Grin | :-D

Displaying float in MessageBox

Steve Kelly25-Mar-06 20:59

Steve Kelly

25-Mar-06 20:59

Could any tell me how I display a float value in a message box.

Your result is: 1234567.5678 - for example

Many Thanks

Steve

Re: Displaying float in MessageBox

Hamid_RT25-Mar-06 21:16

Hamid_RT

25-Mar-06 21:16

I think you use to convert Numeric to String

Example:
int a=123;
TCHAR Buffer[50];

itoa(a,Buffer,10);
MessageBox(Buffer);But if you use 123.23->result 123

Re: Displaying float in MessageBox

ThatsAlok26-Mar-06 17:59

ThatsAlok

26-Mar-06 17:59

WhiteSky wrote:
Example:int a=123;TCHAR Buffer[50];itoa(a,Buffer,10);MessageBox(Buffer);But if you use 123.23->result 123

what about CString::Format or wsprintf command

Re: Displaying float in MessageBox

Hamid_RT25-Mar-06 21:27

Hamid_RT

25-Mar-06 21:27

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dv_wcecrt4/html/erlrfusfcvt.asp[^]

Re: Displaying float in MessageBox

Steve Kelly25-Mar-06 21:38

Steve Kelly

25-Mar-06 21:38

I need to get it in to the message box.

Cheers

Steve

Re: Displaying float in MessageBox

Hamid_RT25-Mar-06 21:54

Hamid_RT

25-Mar-06 21:54

char convert[20];
double Number = 1.123;
_gcvt( Number, 4, convert);

MessageBox(convert);

Re: Displaying float in MessageBox

toxcct26-Mar-06 3:38

toxcct

26-Mar-06 3:38

we're not on the managed forum Frown | :(

Re: Displaying float in MessageBox

Nish Nishant26-Mar-06 7:49

Nish Nishant

26-Mar-06 7:49

v2.0 wrote:
we're not on the managed forum

_gcvt is a native CRT function.

Regards,
Nish

Nish’s thoughts on MFC, C++/CLI and .NET (my blog)
The Ultimate Grid - The #1 MFC grid out there!

Re: Displaying float in MessageBox

toxcct26-Mar-06 20:31

toxcct

26-Mar-06 20:31

oh, don't know why, but i think the prefixing _gc made me wrong :->

Re: Displaying float in MessageBox

ThatsAlok26-Mar-06 18:01

ThatsAlok

26-Mar-06 18:01

Steve Kelly wrote:
I need to get it in to the message box.

TCHAR szString[150];
wsprintf(szString,_T("Your Result is :- %f"),dResult);
AfxMessageBox(szString);

Re: Displaying float in MessageBox

normanS26-Mar-06 18:25

normanS

26-Mar-06 18:25

Good solution.

I'd go for this type of simple, direct solution as well, but using sprintf() and MessageBox() (I still think in Ascii and C)!

Re: Displaying float in MessageBox

eli1502197926-Mar-06 1:44

eli15021979

26-Mar-06 1:44

CString szCaption;
float fResult = 14.58;

szCaption.Format("%f" , fResult);
AfxMessageBox(szCaption);

Regards,
Eli

Problem in Drag & Drop with Splitter Window

Sarvan AL25-Mar-06 19:08

Sarvan AL

25-Mar-06 19:08

Hi all,

I have a splitter window with two list views horizontally.
My aim is to drag an EXE file and drop it in the top view. I have implemented the required drag & drop operations in the top view. Everything works fine. But I need to disable drag & drop in bottom list view. If I try to drop in the bottom view, nothing should happen. How can I achieve this. Give me your hands, please.

Thanks in advance,
Sarvan AL

-- modified at 1:54 Sunday 26th March, 2006

Re: Problem in Drag & Drop with Splitter Window

Michael Dunn26-Mar-06 12:35

Michael Dunn

26-Mar-06 12:35

Make the top pane the window that implements the drop target interfaces (it sounds like the whole frame window is the target currently).

--Mike--
Visual C++ MVP Cool | :cool:

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GetThreadContext always gives the same Context.Eip for all the threads of a program :(

IvanovaIsGod25-Mar-06 18:38

IvanovaIsGod

25-Mar-06 18:38

Hi, 1st post here Smile | :)

I'm trying to figure out the address where the threads of a program are currently executing. This is the code of the internal loop:

<br />
	CONTEXT Context;<br />
	ZeroMemory(&Context,sizeof(Context));<br />
	Context.ContextFlags=CONTEXT_CONTROL|CONTEXT_INTEGER;<br />
<br />
	HANDLE h=OpenT(process.NtProcess->Threads[i].id);  // Expands to OpenThread(....<br />
	SuspendThread(h);<br />
	GetThreadContext(h,&Context);<br />
	ResumeThread(h);<br />
	CloseHandle(h);<br />

All the above works fine. The problem is that for all the threads I get the same Context.Eip Mad | :mad:

Anyway, do you know a simple and better way, so that my head doesn't explode? Big Grin | :-D

Thanks all!

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.