Over the decades of writing code, I’ve found that writing managed code (C#, VB) is much more productive than native code (C++).

This is especially true due to the capabilities of the .Net framework libraries that can be used easily from managed code.

For a given programming task, the number of lines of code is much smaller with managed code, resulting in fewer possibilities of errors.

Below is a sample that takes a very raw C++ program and adds the ability to call managed code to it. This yields a mix of the power, performance of C++ with the capabilities and productivity of the .Net framework.

Start Visual Studio.

File->New->Project->C++ General->Empty Project “CppClr”

Source->Files->Right-Click->Adde New C++ File “CppClr”

Paste in this very simple example:

int main()

{

}

Hit F9 to set a breakpoint on “main”

Hit F5 to run.

You’ll see the breakpoint get hit, and that the program defaults to a Console Application, which means a Console window was created.

(You can also start with your existing C++ project)

Now we want to add some managed code. Paste in this:

 


using namespace System;

int main()
{
	// an uninitialized managed string instance
	String ^ mystr; 
	// use gcnew, for GarbageCollected New to create 
	// a managed object
	// The "L" prefix means use Unicode
	mystr = gcnew String(L"Hello World"); // create a new string
	// call the managed code Console.WriteLine
	Console::WriteLine(mystr);
	Console::WriteLine(L"From C++ Managed Code!");
	Console::ReadLine();
}

 

You’ll get some errors.

First we’ll tell the C++ compiler that we want to use Clr:

Project->Properties->Configuration Properties->C/C++->General->Common Language RunTime Support = “Common Language RunTime Support (/clr)”

These are errors which can be fixed by changing the properties:

cl : Command line error D8016: '/ZI' and '/clr' command-line options are incompatible

Project->Properties->Configuration Properties->C/C++->General->Debug Information Format: Program Database (/Zi)

cl : Command line error D8016: '/clr' and '/Gm' command-line options are incompatible

Project->Properties->Configuration Properties->C/C++->Code Generation->Enable Minimal Rebuild: No

cl : Command line error D8016: '/clr' and '/EHs' command-line options are incompatible

Project->Properties->Configuration Properties->C/C++->Code Generation->Enable C++ Exceptions: Yes with SEH Exceptions (/EHa)

cl : Command line error D8016: '/clr' and '/RTC1' command-line options are incompatible

Project->Properties->Configuration Properties->C/C++->Code Generation->Basic Runtime Checks: Default

CppClr.cpp(5): error C2653: 'Console' : is not a class or namespace name

CppClr.cpp(5): error C3861: 'WriteLine': identifier not found

CppClr.cpp(6): error C2653: 'Console' : is not a class or namespace name

CppClr.cpp(6): error C3861: 'ReadLine': identifier not found

These errors mean we need to add references to some CLR assemblies. However, the project file thinks this is not a CLR project, so the Framework assemblies don’t show in the Add ref dialog.

We can fix that: Right Click on the CppClr Project node in the Solution Explorer->Unload Project.

Then Right Click ->Edit CppClr.vcxproj

That opens the file in the editor.

Add the line

<CLRSupport>true</CLRSupport>

To each configuration(Debug and Release) as shown below:

clip_image001

Now save and close the file, Right Click->Reload the project

Now we can add framework assembly references:

Project->Properties->Common Properties->References->Assemblies->Framework

Add System

clip_image003

Now you have added managed code to a C++ project!

Ctrl-F5 to run it without debugging.