Mixed Mode : Should definitions be in the headers when creating static mixed lib?

Hello,

I am trying to use some .NET stuffs inside already existing native C++ source pool.

I experienced wierd "unresolved symbol" error and ultimately solved the problem but cannot explain why.

Could anyone please tell me what I did Thank you very much,

[ Problem Source Files ]

MixMode.lib (static lib created with /clr)

// ========= "MixMe.h" =========

#pragma once

#include <string>

namespace Minerva { namespace MixMode {

public ref class MixMe

{

protected:

System::Xml::XmlDocument^ _doc;

public:

MixMe(const std:tring& fileName);

virtual ~MixMe();

};

}}

// ========= "MixMe.cpp" ========

#include "MixMe.h"

Minerva::MixMode::MixMe::MixMe(const std:tring& fileName)
{
_doc = gcnew System::Xml::XmlDocument();
}

Minerva::MixMode::MixMe::~MixMe() {}

"MixTool.cpp" (console app with /clr) trying to link with "MixMode.lib"

#include "MixMe.h"
#include <stdio.h>

int main(int argc, char* argv[])
{
printf("Hello, mixed mode operation...\n");

return 0;
}

Eventually, I am getting

Error 1 error LNK2020: unresolved token (06000001) Minerva.MixMode.MixMe::.ctor MixTool.obj
Error 2 error LNK2020: unresolved token (06000002) Minerva.MixMode.MixMe::~MixMe MixTool.obj
Error 3 fatal error LNK1120: 2 unresolved externals G:\PROJECT\Test\MixMode\Debug\MixTool.exe

[ Solved Source Files ] // Very strange why this works ...

MixMode.lib (static lib created with /clr)

// ========= "MixMe.h" =========

#pragma once

#include <string>

namespace Minerva { namespace MixMode {

public ref class MixMe

{

protected:

System::Xml::XmlDocument^ _doc;

public:

MixMe(const std:tring& fileName)

{ _doc = gcnew System::Xml::XmlDocument(); }

virtual ~MixMe() {}

};

}}

// ========= "MixMe.cpp" ========

#include "MixMe.h"

"MixTool.cpp" ==> Same as above. / Link success / Runtime Behaviour OK.

I cannot explain why, but if you add these lines to MixMe.cpp file:

void dummy()

{

}

and then add these lines to main function:

extern void dummy();

dummy();

and also ensure that the main project is made dependent on static library, then the linker errors seem to disappear.

Hi, Viorel,

You are right. Here are what I am planning to do until some fix is coming or some magical options being discovered.

For creating mixed static library ...

[1] WheneverI need C-like functions rather than class object (like mini tool), I think I can separate the definition out of the header file. (So I will have function declaration in header namespace, definition in source files)

[2] When I really need some class object requires .NET classes inside it (I have to create some ref class in this case), I will create them as C# style. (Putting all definitions in the C++ header file)

By doing [1] and [2], my apps (whether it is "main(int, char**)" form or "main(array<System:tring ^> ^args)" form) will not have big problems in linking.

Runtime behavior has not been investigated yet (I hope I am not getting a bomb by the CLR in the middle of exe runs), but time will tell.

I am just stunned how this simple thing makes incredible complexity to the linker. Especially when the maker of the OS is same as the C++/CLI language syntax creator.

Thanks,

Hi,

I found an elegant solution for my problem. (Thanks to Nishant's Book !)

This solution will reduce the overhead of forcing C++/CLI syntax when native developers are trying to use my classes as well.

Still memory management is a big topic, I think I have to study further before delving in.

Thank you,

-- Sunkyu

// ============ LIB HEADER ======================

#include <string>
#include <msclr\auto_gcroot.h>

namespace Minerva {

namespace MixMode {

class MixMe
{
protected:
msclr::auto_gcroot<System::Xml::XmlDocument^> _doc;

public:
MixMe(const std:: string& fileName);
virtual ~MixMe();
};
}
}

// ============ LIB SOURCE ======================

#include "MixMe.h"

using namespace Minerva::MixMode;
using namespace System::Xml;

MixMe::MixMe(const std:: string& fileName)
{
_doc = gcnew XmlDocument();
}

MixMe::~MixMe() {}

// ============ APP CODE ======================

#include "MixMe.h"
#include <stdio.h>

using namespace Minerva::MixMode;

int main(int argc, char* argv[])
{
MixMe* mix = new MixMe("Hello, world");
delete mix;

return 0;
}