Managed C++/CLI

Re: Using a DLL containing MFC functions in a Managed C++ app (Help please)

2-Jun-09 21:42

Hello,

I am experiencing some link errors and would like to ask your help please.

I have a managed C++ workspace, which contains the main app (.exe) and a DLL project that it links to called Editor.dll.

The DLL contains MFC classes for the doc/view classes (e.g. CEditorDoc, CEditorView, etc).

The DLL builds fine, but the main application .exe (managed C++) produces link errors when these DLL classes are used
within it, as demonstrated below:

Linking...
WindowsApplication.obj : error LNK2028: unresolved token "public: static struct CRuntimeClass 
* __stdcall CEditorDoc::GetThisClass(void)" (?GetThisClass@CEditorDoc@@$$FSGPAUCRuntimeClass@@XZ) referenced 
in function "int __thiscall CWindowsApplication::InitInstance(void)"

(Please note the header files are included in the main app file where they are used too).

The link errors all seem to be related to a "GetThisClass()" function which i think seems to have trouble being
exported out of the DLL (it is a member of base class MFC). All other functions seem fine. I also have tried
using a .def file but it doesnt seem to help.

Any help would be greatly appreciated. Thanks!

modified on Wednesday, June 3, 2009 8:34 AM

Mark Salsbery3-Jun-09 11:51

Re: Using a DLL containing MFC functions in a Managed C++ app (Help please)

3-Jun-09 11:51

James1976 wrote:
a DLL project that it links to called Editor.dll.

Links to how? Did you link to the impost library (Editor.lib)?

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

James19763-Jun-09 23:08

Re: Using a DLL containing MFC functions in a Managed C++ app (Help please)

3-Jun-09 23:08

Thanks for your reply.

I couldnt link the .lib (Editor.lib) as the .lib file is only generated if the DLL contains any exports, which it doesnt currently.

I cant export the function that has the link error (the GetThisClass() function) as its not in my code. Its in the MFC base-class and i cant override it in order to place a "declspec(export)" in front of it.

Also i cant export the entire class since it contains managed C++ code and so cannot be exported (only a class that does not contain managed code can be exported it seems).

Any further suggestions would be appreciated? Thanks.

led mike4-Jun-09 4:28

led mike

4-Jun-09 4:28

James1976 wrote:
I couldnt link the .lib (Editor.lib) as the .lib file is only generated if the DLL contains any exports, which it doesnt currently.

Then you have nothing to link to.

James1976 wrote:
I cant export the function that has the link error (the GetThisClass() function) as its not in my code. Its in the MFC base-class and i cant override it in order to place a "declspec(export)" in front of it.

Then you create your own function that you can export and it calls the MFC function.

James1976 wrote:
(only a class that does not contain managed code can be exported it seems).

That is not true. We use a DLL that I authored that is a mixed mode DLL that exports a native C++ class. That class is used in a native Win32 application. The native classes you export cannot use any managed types as parameters because then they would not be a native interface. However they can use managed objects in the implementation.

James1976 wrote:
Any further suggestions would be appreciated?

See here[^]

Re: Using a DLL containing MFC functions in a Managed C++ app (Help please)

Mark Salsbery4-Jun-09 4:52

Re: Using a DLL containing MFC functions in a Managed C++ app (Help please)

4-Jun-09 4:52

Gracias!

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

led mike4-Jun-09 7:30

led mike

4-Jun-09 7:30

Tomorrows is FRIDAY! Jig | [Dance]

Re: Using a DLL containing MFC functions in a Managed C++ app (Help please)

James19764-Jun-09 5:01

Re: Using a DLL containing MFC functions in a Managed C++ app (Help please)

4-Jun-09 5:01

Hi Mike, thanks for your reply.

led mike wrote:
Then you create your own function that you can export and it calls the MFC function.

Even if i add my own function there will still be a compilation error due to the base-class function. I dont think this will work as the base-class function is still directly called by base-class code (that is, the GetThisClass() function is called by the IMPLEMENT_DYNAMIC macro in MFC). I cannot modify MFC to call my own newly added function.

led mike wrote:
That is not true. We use a DLL that I authored that is a mixed mode DLL that exports a native C++ class. That class is used in a native Win32 application. The native classes you export cannot use any managed types as parameters because then they would not be a native interface. However they can use managed objects in the implementation

When i tried to place the "declspec(export)" declaration in front of any class that contains managed C++, it generated a compiler error. I wonder why it worked okay for you, perhaps i dont have something correct in my code? I'll double-check this, thanks.

led mike wrote:
See here[^]

Thanks for your link. I have already tried most of these, including using a .def file (which seemed to accept the .def file but still displayed the linkage errors) and using the declspec(export) for the class as mentioned above.

I have a small sample project that i could email to demonstrate, if yourself or anyone else wouldnt mind taking a look? Any help would be greatly appreciated.

Thanks,
James

led mike4-Jun-09 5:17

led mike

4-Jun-09 5:17

James1976 wrote:
Thanks for your link. I have already tried most of these

Have you seen this[^]?

Re: Using a DLL containing MFC functions in a Managed C++ app (Help please)

James19764-Jun-09 5:21

DRMInitEnvironment function fails............... :(

4-Jun-09 5:21

led mike wrote:
Have you seen this[^]?

Thanks Mike i will give that a read and make sure that i have set up my DLL correctly. Perhaps there's something i have done.

Thanks again,
James

deadlyabbas1-Jun-09 21:31

deadlyabbas

1-Jun-09 21:31

I have suucesfully created Manifext.xml.
DRMInitEnvironment function fails giving me the error code 0x8004cf19 i.e. E_DRM_BROKEN_CERT_CHAIN.

Following is error trace

Running sample OfflinePublishing...
The machine is already activated.
The user is already activated.
A client licensor certificate is already i
DRMInitEnvironment failed. hr = 0x8004cf19

How to return a multidimensional array with a pointer function in Visual C++?

emira671-Jun-09 4:40

emira67

1-Jun-09 4:40

Hello,

I would like to return a multidimensional array from a pointer function.But multidimensional array dimension's will be enormous.For example,width will be 500 and height will be 600.

Could you help me please?

Returning a multidimensional array from pointer function in Visual C++

emira671-Jun-09 4:00

emira67

1-Jun-09 4:00

Hello,

I wrote following code to return multidimensional array from pointer function.Input parameter of this function is one dimensional array, output is pointer that point multidimensional array.

double  **function( array< double>^ data,int width,int height ) 

  {int i;
  //define returning variable that point multidimensional array
  double **R;

 // memory allocation for R
 R=new double *[height];
 for (i=0;i<height;i++)
 {
 R[i]=new double [width];
 }

  // ....


  return R;
 }


  int main( void ) {
  int M=2;
  int N=10;
  int  i,j;
  // define multimensional array 2x10

  array< array< double >^ >^ input = gcnew array< array< double >^ >(M);

for (j=0;j<input->Length;j++){
input[j]=gcnew array<double>(N);}

// define result1 and result 2 pointers and memory allocate  for these  variables

 double **result1;
 result1 = new double *[N];
 for(i=0;i<N;i++)
 {result1[i]=new double [M];}

 double **result2;
 result2 = new double *[N];
 for(i=0;i<N;i++)
 {result2[i]=new double [M];}

 //............


// send first row array of multidimensional array to function

 result1=function(input[0],M,N)

// send second row array of multidimensional array to function

 result2=function(input[1],M,N)

// delete  result1 and result2
for (i=0;i<N;i++)
{delete R[k];}
delete R;}

 return 0;
 }

I built this program succesfully in Visual Studio 2008.When I debug this code,the program computed result1 but during computing result2 in the function here:

R=new double *[height];
for (i=0;i<height;i++)
 {
 R[i]=new double [width];
 }

Visual Studio give this error:

An unhandled exception of type 'System.Runtime.InteropServices.SEHException' occurred in stdeneme.exe Additional information: External component has thrown an exception.

Unfortunately I can't understand this error. How can I overcome of this problem?Could you help me please?

Best Regards..

LNK2005 Redefinition Error on using CLI --already defined LNK2005 error

jobin00700730-May-09 21:15

Re: LNK2005 Redefinition Error on using CLI --already defined LNK2005 error

30-May-09 21:15

I have a native-C++header Unmanaged.h and cpp file Unmanaged.cpp that I need to use with C#. So I am using C++ Interop to use the native files in a managed C++.NET project(CLI) and then reusing the C++.Net project in C#. The name of my managed C++ file is Managed.cpp

I am geting about 40 of the below error(similar error) for each function or variable or object I use in the header file.
error LNK2005: "class CHardwareDelegate11 * pDeckLinkInput1" (?pDelegate11@@3PEAVpDeckLinkInput1@@EA) already defined in Project.obj

Here's how my files look like--

***************Unmanaged.h*********I am not including the whole code.**********

#pragma unmanaged
#pragma once //This should work to make it defined only once

#ifndef BLACKMAGIC_H
#define BLACKMAGIC_H //This should also work to make it defined only once

#include "DeckLinkAPI.h" //External file
#include <vector>
#include <fstream>

IDeckLinkInput* pDeckLinkInput1 =NULL; /********************* These variables also generate redefined error***/
IDeckLinkOutput* pDeckLinkOutput1=NULL ; /********************* These variables also generate redefined error***/

class CHardwareDelegate1 : public IDeckLinkVideoOutputCallback, public IDeckLinkInputCallback
{
//variables
//Functions

}
class Data{
int frametoCapture[40];

}
//Class Objects declared here. /********************* These class objects also generate redefined error***/
//Variables Declared here /********************* These variables also generate redefined error***/
#endif

***************Unmanaged.cpp*********I am not including the whole code.**********

#pragma once
#pragma unmanaged
#ifndef Unmanaged_CPP
#define Unmanaged_CPP

//#include "stdafx.h" //Uncommenting commenting makes no difference.
#include "Unmanaged.h"
#include "Unmanaged.h" //Including Unmanaged.h twice gets no error from the compiler. Only including it in the C++.NET file creates error
#include <signal.h>
#include <boost thread.hpp="">
using namespace std;
#pragma unmanaged

static int SettopBoxCount;
Data Box[12];
int Data::frametoCapture[]={1,4,6,10,14,17,20,22,25,27,31,34,6+30,30+10,30+14,30+17,20+30,22+30,25+30,27+30,1+60,4+60,6+60,10+60,14+60,17+60,20+60,22+60,25+60,27+60,1+90,4+90,6+90,10+90,14+90,17+90,20+90,22+90,25+90,27+90,1+120,4+120,6+120,10+120,14+120,17+120,20+120,22+120,25+120,27+120};

//All class functions and variables defined below.

#endif

*************************Managed.cpp**************************This is the file in which error occurs************

#pragma once
#pragma managed //This makes no difference if its set to unmanaged or managed.
//#include "Unmanaged.h" ///////////////////////////////This is the line which causes the redefinition error///////////////

#pragma managed
int main(array<System::String ^> ^args)
{
Console::WriteLine(L"Hello World");
return 0;
}

All these files are in the same CLR project. The Unmanaged.cpp file option is set not to use the CLR runtime. The Managed.cpp file is set to use the CLR runtime. All the files in the project and the project itself is set not to use precompiled headers. I am working in Visual Studio 2008.

What is causing the error. This is so strange. Please help.

Mark Salsbery31-May-09 9:37

Re: LNK2005 Redefinition Error on using CLI --already defined LNK2005 error

31-May-09 9:37

I would start by getting rid of all these lines, necause these are useless
and redundant in cpp files:

// <code>remove these from Unmanaged.cpp</code>
#pragma once
#pragma unmanaged
#ifndef Unmanaged_CPP
#define Unmanaged_CPP
...
#endif


// <code>remove these from Managed.cpp</code>
#pragma once

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

jobin00700731-May-09 10:18

Re: LNK2005 Redefinition Error on using CLI --already defined LNK2005 error [modified]

31-May-09 10:18

Thanks. I removed the #pragmas and #ifendef's

I was able to find another solution by looking at some examples I looked at.
I actually made all the object variable definitions in the header file to another class I already had in the header file and declared them static.Is there any disadvantage in moving them to the class versus declaring them as global?????? I know global variables are not permitted in C#..and (c++.NET i think)?

I have 2 questions. Please read on.

I have another question relating to performance. My ultimate goal is to use some functions declared in Unmanaged.h in a C# program. I need to know whether this will relate in a performance issue because one of the classes I use (class Data) has a very big size in terms of variables declared and pointers declared.

So essentially my Unmanaged.h looks like this.

*******************Unmanaged.h*********************************
namepace UNMANAGEDNAMESPACE
{
class CHardwareDelegate1 : public IDeckLinkVideoOutputCallback, public IDeckLinkInputCallback
{
//variables
//Functions

//STATIC VARIABLES //These are moved inside the class now
//STATIC FUNCTIONS //These are moved inside the class now
//STATIC OBJECTS //These are moved inside the class now
}
class Data{

int frametoCapture[40];

//About 50 pointer arrays are declared in here each of size 10 bytes.
//About 30 arrays of size 1000 bytes each are declared in here
//Other objects of varying size declared here.

static EntryPointUnmanged() { //Do algorithm.

}
}

}

Now in my Managed.cpp file I did something like this:

*******************Managed.cpp*********************************
namespace Managed
{
public ref class ManagedCLR
{
public:
ManagedCLR (void)
{
pObj = new UNMANAGEDNAMESPACE.Data();
}
~ManagedCLR(void)
{
delete pObj;
}
void EntryPoint(void)
{
//pass through to the unmanaged object
pObj->EntryPointUnmanged(); //Here the managed program accesses my unmanaged program.

}
private:
UNMANAGEDNAMESPACE.Data *pObj; //Here my Unmanaged Class is referenced through a pointer.
};

QUESTION 1)So as seen above I am creating an pointer object of type UNMANAGEDNAMESPACE.Data So i guess the larger the size of UNMANAGEDNAMESPACE.Data class, the larger the memory used will be when i define pObj = new UNMANAGEDNAMESPACE.Data(). Is this true?

Now in my C# file I do the following.
.................Interface.cs...................................
//Add the CLRProject as a reference.

using ManagerCLRproject;

ManagedCLR object1=ManagedCLR();
object1.EntryPoint(); //This should start my UNMANAGED function written in UNMANAGED.H

QUESTION 2)Is there any problems in the above approach. Is there a better approach for reducing memory of the program?

I would appreciate it if you could answer my questions. Thanks.

Mark Salsbery31-May-09 10:40

Re: LNK2005 Redefinition Error on using CLI --already defined LNK2005 error

31-May-09 10:40

jobin007007 wrote:
I actually made all the object variable definitions in the header file to another class I already had in the header file and declared them static.Is there any disadvantage in moving them to the class versus declaring them as global??????

That's fine and ends up being pretty much the same thing, except as
static objects of a class, only one instance will exist. You still need to
define the static instances in ONE cpp file, or you'll get a linker unresolved
external error.

jobin007007 wrote:
QUESTION 1)So as seen above I am creating an pointer object of type UNMANAGEDNAMESPACE.Data So i guess the larger the size of UNMANAGEDNAMESPACE.Data class, the larger the memory used will be when i define pObj = new UNMANAGEDNAMESPACE.Data().

I suppose it's true, but not an issue. No matter what heap an object is created on,
it's still going to take some memory.

jobin007007 wrote:
QUESTION 2)Is there any problems in the above approach. Is there a better approach for reducing memory of the program?

The approach is fine, and a good way to make use of C++/CLI - to interoperate
between managed and unmanaged code. Again, memory is not an issue here...use the
memory you need and free it when you're done with it, just like any programming Smile | :)

Since you're ManagedCLR class holds unmanaged resources (an UNMANAGEDNAMESPACE.Data
object), you may want to implement the ManagedCLR as disposable, so you can free
the unmanaged resource(s) deterministically. (See Destructors and Finalizers in Visual C++[^])
It would look something like this:

public ref class ManagedCLR
{
private:
    UNMANAGEDNAMESPACE.Data *pObj; //Here my Unmanaged Class is referenced through a pointer.

public:
    ManagedCLR()
    {
        pObj = new UNMANAGEDNAMESPACE.Data(); 
    }

    ~ManagedCLR()
    {
        // clean up managed resources here

        // call the finalizer to release unmanaged resources!
        this->!ManagedCLR();
    }

    !ManagedCLR()
    {
        // clean up unmanaged resources here
        delete pObj;
        pObj = 0;
    }

    void EntryPoint(void)
    {
        //pass through to the unmanaged object
        pObj->EntryPointUnmanged(); //Here the managed program accesses my unmanaged program.
    }
};

When used from C# code, you can call Dsipose() to deterministically free unmanaged resources of
a ManagedCLR object. Whwn used from C++/CLI code, just use "delete".

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

modified on Sunday, May 31, 2009 4:48 PM

jobin00700731-May-09 10:48

Re: LNK2005 Redefinition Error on using CLI --already defined LNK2005 error

31-May-09 10:48

Thank you.

I wish there were more examples on all this. I had to spend 2 days looking up examples on the net. and then when i got nowhere I got a couple of books to help me out. Even with the books, small errors here and there would always deter me. It seems like only some people are using CLI INTEROPERABILITY and most people are using the P/Invoke approach. Since performance is critical on my program, this suits me.

Mark Salsbery31-May-09 10:53

Re: LNK2005 Redefinition Error on using CLI --already defined LNK2005 error

31-May-09 10:53

jobin007007 wrote:
most people are using the P/Invoke approach.

I suppose those people aren't able to use C++/CLI, like people who
only know C#, or don't have access to source code to do a C++/CLI
approach.

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

jobin00700731-May-09 11:00

Re: LNK2005 Redefinition Error on using CLI --already defined LNK2005 error

31-May-09 11:00

I suppose those people aren't able to use C++/CLI, like people who
only know C#, or don't have access to source code to do a C++/CLI
approach.

Yes. True. I am working with performance critical video hardware and software and at the same time I need to be able to develop GUI's at a fast pace. So I need to use with C++ with C#. I don't have any options!! Smile | :)

Mark Salsbery31-May-09 11:08

Re: LNK2005 Redefinition Error on using CLI --already defined LNK2005 error

31-May-09 11:08

jobin007007 wrote:
I am working with performance critical video hardware and software and at the same time I need to be able to develop GUI's at a fast pace. So I need to use with C++ with C#.

Same here.. WPF/C# for the GUI and general housekeeping stuff, and
C++/CLI to talk to my unmanaged C++ code...works sweet!

Cheers,
Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

jobin00700731-May-09 12:07