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Problems importing functions from a DLL in a C++ program

Hi all... I need your help again:

I've programmed the following DLL (I only show the function definitions):

#include <windows.h>
#include "handkey.h"
#pragma hdrstop

class TSerial
{
public:
BOOL      Error;
MSG_FMT      MessageOut, MessageIn;

TSerial( );               // Constructor
~TSerial( );        // Destructor
void SendMessage( ); // Envía un mensaje
void ReceiveMessage( ); // Recibe el mensaje

private:
HANDLE      hCom;
LPSTR      Message;
};

BOOL APIENTRY DllEntryPoint( HINSTANCE hDLL, DWORD dwReason, LPVOID Reserved )
{
hInstance = hDLL;
switch( dwReason )
{
       case DLL_PROCESS_ATTACH:
       {
            break;
       }
       case DLL_PROCESS_DETACH:
       {
            break;
       }
}
return TRUE;
}

BOOL APIENTRY Setup( )
{
..................
}

TSerial::TSerial( )
{
................................
}

TSerial::~TSerial( )
{
............................
}

void TSerial::SendMessage( )
{
................................
}

void TSerial::ReceiveMessage( )
{
.............................
}

BOOL APIENTRY HandKey_RequestTemplate( BYTE Reader )
{
...............................
}

BOOL APIENTRY HandKey_RequestDatalog( BYTE Reader )
{
................................
}

The exported functions are Setup, HandKey_RequestTemplate and HandKey_RequestDatalog, so the .DEF file is:

LIBRARY HANDKEY
DESCRIPTION 'Rutinas que manejan el HandKey Reader'
CODE PRELOAD MOVEABLE DISCARDABLE
DATA PRELOAD MOVEABLE SINGLE
EXPORTS Setup
HandKey_RequestTemplate
       HandKey_RequestDatalog

When I compile the program, and then link it, I got the following linking error;

Info :Linking E:\Trabajos\HandKey\DLL\handkey.dll
Warn :Warning: Attempt to export non-public symbol 'Setup'
Warn :Warning: Attempt to export non-public symbol 'HandKey_RequestTemplate'
Warn :Warning: Attempt to export non-public symbol 'HandKey_RequestDatalog'

The million question, WHY??????? Why cannot I export those functions????? How can I do it????? I think this problem is related to the use of a class because I have a similar DLL but made in C, not in C++ and it compiles and links well.

Thanks a lot in advance :)
Jaime

ASKER CERTIFIED SOLUTION

rwilson032697

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demarcy

ASKER

rwilson... I have done so and it compiles well.... but in that case, I cannot use the functions in the DLL from an EXE program.

I have in the EXE program the following declarations:

#define DLLIMPORT __declspec(dllimport)

DLLIMPORT BOOL APIENTRY HandKey_RequestTemplate( BYTE );
DLLIMPORT BOOL APIENTRY HandKey_RequestDatalog( BYTE );

When I compile the program, linker gives the errors:
Info :Linking E:\Trabajos\HandKey\DLL\prueba.exe
Error:Error: Unresolved external 'HandKey_RequestTemplate' referenced from module prueba.c
Error:Error: Unresolved external 'HandKey_RequestDatalog' referenced from module prueba.c

How can I import it properly? The PRUEBA program is in C.

Thanks
Jaime

demarcy

ASKER

One strange thing is that if I use IMPDEF to generate a DEF file of an example program I got:

LIBRARY DLLSKEL.DLL

EXPORTS
DLLFunction1 @1
DLLFunction2 @2
__DebuggerHookData @3

While if I do it with my program, I get:

LIBRARY HANDKEY.DLL

EXPORTS
@HandKey_RequestDatalog$qqsuc @3 ; HandKey_RequestDatalog(unsigned char)
__stdcall
@HandKey_RequestTemplate$qqsuc @2 ; HandKey_RequestTemplate(unsigned
char) __stdcall
@Setup$qqsv @1 ; Setup() __stdcall
__DebuggerHookData @4

Why is this?

demarcy

ASKER

I've proved that those letters, for example, $qqsv after Setup is placed only by the CPP compiler, how can I do it so that in the LIB file only appear Setup, instead of Setup$qqsv?

Thanks
Jaime

rwilson032697

I think what you are seeing is the name mangling that the compiler does. You need to specify the pascal calling convention (either pascal (or _pascal) or stdcall (or _stdcall)) in the function declarations.

Cheers,

Raymond.

demarcy

ASKER

Thanks.. I have solved the problem.. it was obvious :)

Bye