How to step into a native C++ dll in Visual Studio?

I'm debugging my C# unity code through visual studio, and I would like to step into my native C++ code. From C#, I am loading my native c++ plugin using the LoadLibrary function.

Code (CSharp):

1. [DllImport("kernel32.dll")]public static extern IntPtr LoadLibrary(string dllToLoad );

I can:

• Debug my C# code
• Load my C++ dll
• Call my C++ dll functions

I can't ( and need help with ):

• Stepping into my C++ dll functions
• Seeing my C++ dll in Visual Studio's modules window

Is Visual Studio not loading my pdb? I've already set the dll's pdb location in Visual Studio Tools-->Options-->Debugging->Symbols

Screenshot of my modules window after calling LoadLibrary() on my dll: http://puu.sh/pFRvc/fa9d73a3db.png

 

I think you could if the solution included both the c# and c++ projects, which the dependency c# -> c++ library, you may be able to do this.. but I have not, and not really finding any 'how-to' do that.

 

Good idea, but unfortunately it didn't work.

 

From your screenshot, all loaded modules are managed ones (e.g: .NET based).
There's a debugger setting in Visual Studio for whether you want managed debugging, native, or both (mixed).

Check out this link, it might help you in setting it up: https://msdn.microsoft.com/en-us/library/kbaht4dh.aspx

 

I don't have a Debugging option in my Configuration Properties



If I right click on my C++ project and left click on Properties, I can set the Debugger Type of my C++ project.
However, if I right click on my C# project and left click on Properties, Visual Studio flashes and then then nothing happens...

 

If I don't use Visual Studio Tools for Unity, can I enable mixed debugging?

 

Clarification!
My laptop runs 64-bit Windows 10. I am creating my dll with these commands:

C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\bin\amd64\vcvars64.bat
"C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\bin\amd64\cl.exe" tacgame.cpp tacclient.cpp tacserver.cpp taccommon.cpp tacutil.cpp /W4 /WX /LD /Fetacwindowsx64.dll /EHs /Zi /nologo /MDd /DLL

In Unity, I'm currently building the Windows x86_64 standalone,
( But I'll do whatever it takes to have convenient debugging )


I have: 1. My source code, 2. My dll, and 3. My pdb, which are the three ingredients for happiness.
Happiness being able to step through my C# code in Visual Studio, press F11, and now be stepping through my C++ code.

( C# code on the left, C++ code on the right )

 

What are the debugger settings in visual studio? did you try to see if you have the option to enable native debugging?

Are you debugging using Unity tools for VS ? this is what it looks like from the image above. i guess you cannot debug native code using that.

 

do you have any breakpoints in the c++ code?

 

Hope this helps someone.
I used this tutorial to build the C++ Lib: https://levelup.gitconnected.com/in...-as-plugins-a-step-by-step-guide-17ad70c2e3b4

Than set: In the Properties pane, under Linker > Debugging, select Yes (/ASSEMBLYDEBUG) for Debuggable Assembly.
discribed here: https://docs.microsoft.com/en-us/visualstudio/debugger/debugging-dll-projects?view=vs-2019

Than you can debug your native C++ Dlls.

1. Set a Breakpoint
2. In the C++ VS Project Debug -> Attach to Process...
3. In Attach to Select only Native code
4. Search for Unity and select the Unity with the Project name in Title
5. Important: There are no code changes allowed in the C++ File. Otherwise the debugger will not work!
6. But you can now change the C++ Code and hot Apply Code Changes in C++ in runtime.

 

Can confirm that this is working with Unity 2019.4.12, Visual Studio 2019 (16.11.5) and Window 11.

 

I see the only way to debug the native dll line by line is to attach its project to Unity.exe after running the simulation. I am trying to do this but always VS 2019 says that "The breakpoint will not be hit. No symbols have been loaded for this document".
Can someone please provide any guidance how to attach the native VS 2019 dll project to Unity.
Just forgot to mention that the pdb file is there as well.

 

Works for Win 10, Unity 2021.2.17f1 and VS 2022.

Few notes:

- the "Properties pane" is when u right click on the PROJECT (not a solution) in Visual Studio and select "Properties".
- if u can't open the Properties pane - in Visual Studio go to Tools>Options>Tools for Unity>General and enable the "Access to project properties" option.
- VS 2022 does not have the Linker tab in Properties pane. I skipped this step and it still worked fine.
- I was confused about the 2nd point from the original post and in general I did not understand how you debug a cpp file in a project where only the dll of said file exists. That was because I was thinking that you will be debugging inside the C# UNITY PROJECT, which is WRONG. You are performing a debug inside a C++ PROJECT, that produced the dll in the first place. That is why you need to Attach to Process.

If nothing works, try this just in case:

- Go to Debug tab in Properties pane and turn on "Enable native code debugging". Do it for TWO projects: "Assembly-CSharp" and "Assembly-CSharp.Player"
- Turn OFF "Enable just my code" in Visual Studio Tools->Options->Debugger.

 

Here is my approach towards debugging native c++ code used within a Unity project