Import Native C++ dll into C++ Class Library

  • Thread starter Thread starter rhythmchicago
  • Start date Start date
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rhythmchicago

I'm trying to write a dll in native c++, then wrap it in a c++ class
library.

I know I'm missing a few steps. Can someone please point me in the
right direction? I read that VS2008 had added some features to make
using native c++ dlls easier, but I haven't found much documentation
on this.

This is the native c++ dll:

#pragma once

typedef int (__stdcall *mbmTransmit)( const char *inMessage, const int
inLength );

class __declspec(dllexport) CModbusMaster
{

public:

CModbusMaster( bool inIsTcp );
~CModbusMaster(void);

char txMessage[255];
char rxMessage[255];

bool IsTcp;


// The Callback functions
mbmTransmit TransmitFunction;


// Enum some return values
enum
{
MB_SUCCESS = 0,

MB_BADFUNC = 0x01, // Illegal Function
MB_BADADDR = 0x02, // Illegal Data Address
MB_BADDATA = 0x03, // Illegal Data Value
MB_SLAVEFAILURE = 0x04, // Slave Device Failure
MB_BUSY = 0x06, // Target is busy with another request
MB_NORESP = 0x0B, // No response from target
MB_DEVNOTSET = 0x10, // device not properly set up

MBM_INVALID_PARAMETER = -1,
MBM_PACKET_ERROR = -2,
MBM_BAD_ADDRESS = -3,
MBM_BAD_BYTECOUNT = -4,
MB_CRC_ERROR = -5,
MBM_PFTRANSMIT_NULL = -10

};




/* FC 0x03 */
int ReadMulitpleRegisters( int inAddress,
int inStartRegister,
int inLength,
int *outValues );

/* FC 0x10 */
int WriteMultipleRegisters( int inAddress,
int inStartRegister,
int inLength,
int *inValues );






private:

char *ptxMessage;

void initMessage ( int inAddress, int inFunctionCode, int
inPDUByteCount );
void insertWord ( int Value );
void insertByte ( int Value );
int getMessageWord ( int Offset );


};


And this is c++ class library I'm trying to import into:


#pragma once

using namespace System;

#include "d:/srcroot/adcModbus/Master/v1/modbus_master/modbus_master/
ModbusMaster.h"

namespace adcModbusMasterTCP {

public ref class CModbusMasterTCP
{
public:

CModbusMasterTCP(void);
~CModbusMasterTCP(void);


int ReadMulitpleRegisters( int inAddress,
int inStartRegister,
int inLength,
int *outValues );

/* FC 0x10 */
int WriteMultipleRegisters( int inAddress,
int inStartRegister,
int inLength,
int *inValues );

private:

CModbusMaster *mbm;

};
}


In the constructor of the class library, I make a new ModbusMaster.


CModbusMasterTCP::CModbusMasterTCP(void)
{
mbm = new CModbusMaster(true);
}

Everything compiles fine, but it won't link.

Error 1 error LNK2020: unresolved token (06000002)
adcModbusMasterTCP.CModbusMasterTCP::~CModbusMasterTCP
adcModbusMasterTCP.obj adcModbusMasterTCP
Error 2 error LNK2020: unresolved token (06000003)
adcModbusMasterTCP.CModbusMasterTCP::ReadMulitpleRegisters
adcModbusMasterTCP.obj adcModbusMasterTCP
Error 3 error LNK2020: unresolved token (06000004)
adcModbusMasterTCP.CModbusMasterTCP::WriteMultipleRegisters
adcModbusMasterTCP.obj adcModbusMasterTCP

I'm obviously missing a step. Can anyone point me in the right
direction?

Thanks in advance!
 
Hi rhythmchicago!
Everything compiles fine, but it won't link.

Error 1 error LNK2020: unresolved token (06000002)
adcModbusMasterTCP.CModbusMasterTCP::~CModbusMasterTCP
adcModbusMasterTCP.obj adcModbusMasterTCP
Error 2 error LNK2020: unresolved token (06000003)
adcModbusMasterTCP.CModbusMasterTCP::ReadMulitpleRegisters
adcModbusMasterTCP.obj adcModbusMasterTCP
Error 3 error LNK2020: unresolved token (06000004)
adcModbusMasterTCP.CModbusMasterTCP::WriteMultipleRegisters
adcModbusMasterTCP.obj adcModbusMasterTCP
Click to expand...

You need to link against the Import-LIB of your DLL!

Therefor you also need to use "__declspec(dllmport)"... for more basics
see "createing simple DLL" on codeproject


--
Greetings
Jochen

My blog about Win32 and .NET
http://blog.kalmbachnet.de/
 
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