still problems with linker error

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November 10th, 2003, 09:13 AM

teo.castoro

Junior Member

Join Date: Nov 2003

Location: milan

Posts: 14

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still problems with linker error

Hi! I'm tryin' to create a simple dll with an included module (Form7) with BCB5 but I’ve some linking problems.
This is the code:

PHP Code:


		
			
// Mydll.cpp



//---------------------------------------------------------------------------



#include <vcl.h>

#include <windows.h>

#pragma hdrstop

//---------------------------------------------------------------------------

#include "Unit7.h"

#pragma argsused

int WINAPI DllEntryPoint(HINSTANCE hinst, unsigned long reason, void* lpReserved)

{

Form7=new TForm7(NULL);

Application->OnShortCut=Form7->KeyEvent;

KeyPressed = false;

return 1;

}

//---------------------------------------------------------------------------

extern "C"

{

bool __export GetEvent()

        {

        bool ret=false;

        if (KeyPressed)

                {

                ret=true;

                KeyPressed=false;

                }

        return ret;

        }

}



// Unit7.cpp



//---------------------------------------------------------------------------



#include <vcl.h>

#pragma hdrstop



#include "Unit7.h"

//---------------------------------------------------------------------------

#pragma package(smart_init)

#pragma resource "*.dfm"

TForm7 *Form7;

bool KeyPressed;

//---------------------------------------------------------------------------

__fastcall TForm7::TForm7(TComponent* Owner)

        : TForm(Owner)

{

}



//---------------------------------------------------------------------------

void __fastcall KeyEvent(Messages::TWMKey &Msg, bool &Handled)

{

if(Msg.CharCode == VK_ESCAPE)

    {

        KeyPressed=true;

        Handled = true;

    }

}



// Unit7.h



//---------------------------------------------------------------------------



#ifndef Unit7H

#define Unit7H

//---------------------------------------------------------------------------

#include <Classes.hpp>

#include <Controls.hpp>

#include <StdCtrls.hpp>

#include <Forms.hpp>

//---------------------------------------------------------------------------

class TForm7 : public TForm

{

__published:    // IDE-managed Components

private:    // User declarations

public:        // User declarations

        __fastcall TForm7(TComponent* Owner);

        void __fastcall KeyEvent(Messages::TWMKey &Msg, bool &Handled);

};

//---------------------------------------------------------------------------

extern PACKAGE TForm7 *Form7;

extern bool KeyPressed;

//---------------------------------------------------------------------------

#endif

When I compile, everything it’s OK, but I’ve this linker error:

PHP Code:


		
			
[Linker Error] Unresolved external '__fastcall TForm7::KeyEvent(Messages::TWMKey&, bool&)' referenced from D:\DOCUMENTS AND SETTINGS\MATTEO\DESKTOP\PROVALADLL\MYDLL.OBJ

I’ve tried to change the position of the declaration of void __fastcall KeyEvent (I think this is the problem), but I still have errors of this kind.
Anyone can help me, please?
Bye,
Castoro

PS:I’ve forgot to say that the dll should simply return true if the key “Esc” has been pushed (without generating a OnKeyPress event – so using the OnShortCut event of TApplication), else return false in the other cases (generating a OnKeyPress event).
Bye

November 10th, 2003, 01:22 PM

Scorpions4ever

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In unit7.cpp, change this line:
void __fastcall KeyEvent(Messages::TWMKey &Msg, bool &Handled)

to this:
void __fastcall TForm7::KeyEvent(Messages::TWMKey &Msg, bool &Handled)

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November 11th, 2003, 05:33 AM

teo.castoro

Junior Member

Join Date: Nov 2003

Location: milan

Posts: 14

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Yes,this is the error. now my dll is well compiled and linked but still doesn't do what I need. If I use it in a simple program as:

PHP Code:


		
			
//---------------------------------------------------------------------------



#include <vcl.h>

#pragma hdrstop



#include "Prova_src.h"

//---------------------------------------------------------------------------

#pragma package(smart_init)

#pragma resource "*.dfm"

TForm1 *Form1;

FARPROC myfunc;

//---------------------------------------------------------------------------

__fastcall TForm1::TForm1(TComponent* Owner)

        : TForm(Owner)

{

HINSTANCE mylib = LoadLibrary("trigger3sec.dll");

 if(mylib){

  myfunc = GetProcAddress(mylib,"_GetEvent");

 }

}

//---------------------------------------------------------------------------



void __fastcall TForm1::Timer1Timer(TObject *Sender)

{

if((myfunc) && myfunc()){

  if (Color==clBtnFace) Color=clRed;

  else Color=clBtnFace;

 }

}

//---------------------------------------------------------------------------

if I push the "Esc" key my dll doesn't respond with the Form7->KeyEvent as should do.
It could be a problem due to the fictitious form (Form7) that I've decided to use??
Is there a way to use an event in a dll without using this fictitious form?
And in this case where I should declare this function in the dll?
Thanks for your help, hoping u will have still some time to dedicate to my problem (and to understand my English,too;-))!
Bye

still problems with linker error

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