Re: Linking problem - C / C++ / MFC Discussion Boards

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Re: Linking problem

Cedric Moonen23-Nov-09 0:10

Cedric Moonen

23-Nov-09 0:10

~~Where did you put it ? And what do you mean with "its not working" ?~~

Anyway, as already suggested (by someone else also), putting the implementation of your function in a header file is very bad practice.

EDIT: it won't work anyway because if your file is include from two completely different cpp files, then you will end up with a duplicate function at compile time. So, move your implementation in a separate cpp file instead.

Cédric Moonen
Software developer

Charting control [v2.0]
OpenGL game tutorial in C++

Re: Linking problem

KASR123-Nov-09 0:13

KASR1

23-Nov-09 0:13

Yes i know that. To solve some issues they added function definition in header file.
I have added #pragma at the beginning of header file. Still same error(already defined).

Re: Linking problem

KASR123-Nov-09 0:35

KASR1

23-Nov-09 0:35

Please see 'Stuart Dootson' reply.

Re: Linking problem

Richard MacCutchan23-Nov-09 0:02

Richard MacCutchan

23-Nov-09 0:02

Don't put implementation code in header files. Place this function in one .cpp file only.

Re: Linking problem

KASR123-Nov-09 0:10

KASR1

23-Nov-09 0:10

For some issues we have included one function definition in header file.
That we cannot change.

However

#pragma once

should slove the problem. But it doesnt why?

Re: Linking problem

Cedric Moonen23-Nov-09 0:14

Cedric Moonen

23-Nov-09 0:14

KASR1 wrote:
For some issues we have included one function definition in header file.
That we cannot change.

Why ? And why not trying to fix the original issue ?

Cédric Moonen
Software developer

Charting control [v2.0]
OpenGL game tutorial in C++

Re: Linking problem

KASR123-Nov-09 0:19

KASR1

23-Nov-09 0:19

Actually this project is a static library. When linking with some exe/dll we are getting CTime link error. So we have defined a function with CTime and including that header in the exe/dll.

Re: Linking problem

Richard MacCutchan23-Nov-09 0:22

Richard MacCutchan

23-Nov-09 0:22

You do not seem to understand the difference between declaration and implementation. Your header file should contain only the declaration e.g.

void TestMethod();

The implementation code should go in a single source file (Test.cpp) as follows:

void TestMethod()
{
    // body of the TestMethod function
}

Try reviewing the relevant sections in your C/C++ guides for further explanations.

Re: Linking problem

KarstenK23-Nov-09 0:13

KarstenK

23-Nov-09 0:13

is in Test2 the methode ALSO defined? Dead | X|

Press F1 for help or google it.
Greetings from Germany

Re: Linking problem

KASR123-Nov-09 0:14

KASR1

23-Nov-09 0:14

No.

Re: Linking problem

Stuart Dootson23-Nov-09 0:22

Stuart Dootson

23-Nov-09 0:22

Mark the method as 'inline', or place it inside an anonymous namespace:

namespace {
void TestMethod()
{
..........
}
}

[edit] To expand on that answer - by including a function body in a header, it's defined in lots of .obj files. When you link, the linker attempts to merge contents of all object files into an executable. As you have lots of functions with the same signature, it can't do that. The suggestions I've given prevent that. The inline suggestion should stop the function ever existing in the object file, while ht eanonymous namespace thing stops the function being visible outside each of the object files.[/edit]

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

Re: Linking problem [modified]

KASR123-Nov-09 0:26

KASR1

23-Nov-09 0:26

Yes it solves the linking problem.
Its now clear. Thanks.

modified on Monday, November 23, 2009 6:33 AM

Re: Linking problem

john563223-Nov-09 3:05

john5632

23-Nov-09 3:05

use \FORCE:MULTIPLE in linker->command

Interact with Autocad.

Paulraj G22-Nov-09 22:42

Paulraj G

22-Nov-09 22:42

Hi...

How to interact with Autocad from vc6.0.

I have to get the x, y points and radius from autocad drawing...

Please help me.

Thanks...

G.Paulraj

Re: Interact with Autocad.

KarstenK23-Nov-09 0:11

KarstenK

23-Nov-09 0:11

Read the file data and convert it or AutoCad are interfaces like COM. It dont know. Unsure | :~

It is very special stuff
=> you should try it in an AutoCad Forum or so.

Press F1 for help or google it.
Greetings from Germany

Listbox problem

Chandrasekharan P22-Nov-09 22:15

Chandrasekharan P

22-Nov-09 22:15

I have 2 listbox in my application. Now when i click on the first list box item the same item will be displayed on the second listbox and the first listbox item remains selected. now how do i remove the selected item from the second listbox if i again click on the selected item in the first listbox?

Re: Listbox problem

lxkjlzz22-Nov-09 22:24

lxkjlzz

22-Nov-09 22:24

you can remove listbox2's item when click listbox1 item,Then add listbox2's item Poke tongue | ;-P

m_listbox2.ResetContent();

Re: Listbox problem

KarstenK23-Nov-09 0:17

KarstenK

23-Nov-09 0:17

you need to write that code in the message handlers of the combo box. Use the VC wizard to create a message onhandler for "CBN_SELCHANGE" or other approbiate messages.

Press F1 for help or google it.
Greetings from Germany

Re: Listbox problem

dxlee23-Nov-09 5:51

dxlee

23-Nov-09 5:51

There is not even a combobox involved. Read the original question carefully before you give an answer!

using WPF in MFC applcation.

Anu_Bala22-Nov-09 21:52

Anu_Bala

22-Nov-09 21:52

Hi, I want to create MFC dailogs with glossy buttons.
So, i want to use WPF controls in MFC applcaiton.
Can you give any tutorials or samples for using it?

Anu

is it possible to handle voice messages in vc++6.0

eswar pothula22-Nov-09 20:47

eswar pothula

22-Nov-09 20:47

hi every body.....

i have a small problem in my application.......

record and save a voice message(or)file using our application.

please help me

thanks in advace...

Re: is it possible to handle voice messages in vc++6.0

Richard MacCutchan22-Nov-09 21:20

Richard MacCutchan

22-Nov-09 21:20