Sample: Mixing Unmanaged C++, C++/CLI, and C# code

Back in May 2005 I posted an article on how to mix C# and C++ code in single assembly.

I still get emails asking for samples. So I created this simple sample. Enjoy.

We have this simple unmanaged C++ class UnmanagedFoo:

E:\sample\vc\mixed>more ufoo.h
#include <stdio.h>
class UnmanagedFoo
{
public:
UnmanagedFoo() {printf("Constructing UnmanagedFoo\n");}
~UnmanagedFoo() {printf("Destructing UnmanagedFoo\n");}
void ShowYourself();
};

And implementation:

E:\sample\vc\mixed>more ufoo.cpp
#include "ufoo.h"
void UnmanagedFoo::ShowYourself()
{
printf("UnmanagedFoo\n");
}

Another simple C++/CLI class ManagedFoo, with a member of UnmanagedFoo.

E:\sample\vc\mixed>more mfoo.cpp
#include "ufoo.h"
#using <mscorlib.dll>
using namespace System;

ref class ManagedFoo
{
public:
ManagedFoo()
{
Console::WriteLine("Constructing ManagedFoo");
m_foo = new UnmanagedFoo();
if (!m_foo) {
throw gcnew OutOfMemoryException();
}
}
~ManagedFoo() {ShowDestruction();}
!ManagedFoo() {ShowDestruction();}
void ShowYourself()
{
Console::WriteLine("ManagedFoo");
m_foo->ShowYourself();
}
private:
void ShowDestruction()
{
if (m_foo) {
delete m_foo;
}

        Console::WriteLine("Destructing ManagedFoo");
}
UnmanagedFoo *m_foo;
};

C# class Bar uses ManagedFoo:

E:\sample\vc\mixed>more bar.cs
using System;
class Bar
{
public static void Main()
{
ManagedFoo foo = new ManagedFoo();
foo.ShowYourself();
}
}

Let us build the project.

First, compile ufoo.cpp into (unmanaged) obj file.

E:\sample\vc\mixed>cl.exe /Zi /MD /c ufoo.cpp
Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 14.00.50727.42 for 80x86
Copyright (C) Microsoft Corporation. All rights reserved.

ufoo.cpp

And mfoo.cpp

E:\sample\vc\mixed>cl.exe /Zi /clr /c mfoo.cpp
Microsoft (R) C/C++ Optimizing Compiler Version 14.00.50727.42
for Microsoft (R) .NET Framework version 2.00.50727.88
Copyright (C) Microsoft Corporation. All rights reserved.

mfoo.cpp

And bar.cs, referencing mfoo.obj

E:\sample\vc\mixed>csc /target:module /addmodule:mfoo.obj bar.cs
Microsoft (R) Visual C# 2005 Compiler version 8.00.50727.88
for Microsoft (R) Windows (R) 2005 Framework version 2.0.50727
Copyright (C) Microsoft Corporation 2001-2005. All rights reserved.

Finally, let’s link everything together.

E:\sample\vc\mixed>link mfoo.obj ufoo.obj bar.netmodule /entry:Bar.Main /out:test.exe /subsystem:console /ltcg
Microsoft (R) Incremental Linker Version 8.00.50727.42
Copyright (C) Microsoft Corporation. All rights reserved.

Generating code
Finished generating code

Now we have a single file assembly test.exe, mixed with unmanaged C++, C++/CLI, and C#.

E:\sample\vc\mixed>test
Constructing ManagedFoo
Constructing UnmanagedFoo
ManagedFoo
UnmanagedFoo
Destructing UnmanagedFoo
Destructing ManagedFoo

We can also put ufoo.obj into a lib and link the lib in the final step, instead of using ufoo.obj directly.

E:\sample\vc\mixed>lib ufoo.obj /out:ufoo.lib
Microsoft (R) Library Manager Version 8.00.50727.42
Copyright (C) Microsoft Corporation. All rights reserved.

E:\sample\vc\mixed>link mfoo.obj ufoo.lib bar.netmodule /entry:Bar.Main /out:test2.exe /subsystem:console /ltcg
Microsoft (R) Incremental Linker Version 8.00.50727.42
Copyright (C) Microsoft Corporation. All rights reserved.

Generating code
Finished generating code

E:\sample\vc\mixed>test2
Constructing ManagedFoo
Constructing UnmanagedFoo
ManagedFoo
UnmanagedFoo
Destructing UnmanagedFoo
Destructing ManagedFoo

Comments

• Anonymous
  May 20, 2006
  Awesome!
• Anonymous
  May 20, 2006
  This is nice. Can you show a sample of how to use a COM Object (say which doesn't support IDispatch) to be use with C++/CLI (which inturn could be used by C#).
• Anonymous
  July 05, 2006
  The comment has been removed
• Anonymous
  July 18, 2006
  How to do all this in the context of Visual Studio 2005 ?. There does not seem to be a way to mix different manage languages in one assembly.
• Anonymous
  July 19, 2006
  Keith1000,
  
  I don't think this is possible in Visual Studio 2005.
• Anonymous
  July 23, 2006
  Thank's for this nice tuto' Junfeng.
  Does this procedure work to use unmanaged C++ with VB.Net? Or is that a specific case?
• Anonymous
  July 31, 2006
  I never used VB.Net, but I imagine it should work, as long as the compiler supports netmodule.
• Anonymous
  August 14, 2006
  Thanks for this sample. Is it possible to call a C# dll from a C application? All of the text I find is about C++ as unmanaged code interoping with managed code. How about C->C#? Please, can anyone point me to something useful?
  
• Anonymous
  August 14, 2006
  You can use CLR hosting.
  
  http://msdn.microsoft.com/library/en-us/cpguide/html/cpconhostingcommonlanguageruntime.asp
  
• Anonymous
  June 03, 2009
  PingBack from http://castironbakeware.info/story.php?title=junfeng-zhang-s-windows-programming-notes-sample-mixing-unmanaged