I have a C# program from which I am calling some functions/variables from C++.
The C++ program itself runs fine, and is checked. But, when I build this DLL and use it for C#, there is some bug in the interfacing code that is preventing me to get the correct result in C#.
Most probably, there is some error in export variables/exported functions giving out the results, which I want to check.
My primary question is : How do I debug this DLL, as in by putting breakpoints etc. and following along by seeing the results as we could do for any other program?
Assuming you have source code and debug symbols for the native (C++) DLL, you can check the "Enable unmanaged code debugging" option on the "Debug" tab of the managed (C#) EXE project, and then set breakpoints, inspect variables etc. in the C++ code as usual. You can add the C++ project to the solution, or just open a single C++ source code file and set breakpoints there.
If you want to debug the DLL, you should work in your C++ environment, put breakpoints in your c++ code, but use the executable generated by c#.
The best way to debug this kind of scenario, is by either using Visual Studio mixed mode debugging (via devenv /debugexe yourapp.name.exe command) or using Windbg + SOS extension (steeper learning curve, but this would show a lot more information, like you type sizes in native and managed code)
To learn how to use Windbg + SOS, please see Advanced .NET Debugging by Mario Hewardt
Note, that often these kind of issues are caused by
1) Incorrectly chosen C# data type to use with C++ APIs
2) Incorrectly specified / unspecified function calling convention
http://blogs.msdn.com/b/adam_nathan/archive/2003/05/21/56690.aspx
Related
I've really been banging my head against the proverbial wall over this one.
I have a solution which contains both C# and C++ code projects.
I often call the C++ DLLs, which are compiled in this project from the C# via P/Invoke. No problemo. All the requisite debugger settings through the *.sln file, as well as the C++ and C# files, have been properly set, to the best of my knowledge. Note: I often am able to debug similarly P/Invoked C++ code with no issues!
Naturally, I figured that, perhaps, the symbols weren't loading -- yet, upon opening the modules window, I discovered that the DLL into which I am attempting to step isn't even listed! Running the function in my C# program does indeed use the DLL (I get the correct output), but, whilst watching the Modules window, the DLL still does not appear.
Does anyone have an idea of what's going on?
tl;dr --> I have a fair amount of experience with debugging P/Invoked C++. However, the DLL I wish to debug does not even appear in the Modules list (so I obviously am not able to step into it if the VS debugger appears to be completely unaware of its existence).
Thanks in advance!!
Cheers!
-Kadaj
My guess would be that you do not have debugging turned on for unmanaged code. Go to the Start-up project's Properties->Debug tab. Check "Enable unmanaged code debugging".
How do I debug a native code project from inside a managed code project? I am using C# to call C++ code and need to debug the C++ code. Otherwise, I must exit out of the project, open the C++ project, create a tester and then debug the code. This is horrible.
Add your c++ project to the solution containing your C# code
In the C# project properties pages, under the debug tab
Check "Enable unmanaged code debugging"
If that doesn't work you also need to open the Options dialog from either the Debug or the Tools menu (in VS2017) and go to Debugging->General. Check the option
"Suppress JIT optimization on module load (Managed only)."
You will then be able to debug into your C++/CLI and C++ code. (This final tip comes from Kim Togo Andersen.)
In the debugging options for visual studio you HAVE to specify the correct debugger type.
Open up the property dialog window for the project, and under the Configuration Properties select Debugging. For the Debugger Type option, select the property that applies:
This can be auto, or mixed. I prefer mixed as it is explicitly stating you want both managed and native debugging.
As a side note, you can pick native only, but you won't be able to set a breakpoint in managed code. I'm not sure if this is an issue for you or not.
If you pick managed only, you obviously won't hit any breakpoints in native code.
I have a VB6 object that is wrapped by a .NET class. As far as I recall it is possible to step through a VB6 object by simply running the VB6 library and inserting a breakpoint at the desired location.
However this does not appear to be working in my case. I have attempted to recompile the VB6 object and re-reference it in my .NET project but this doesn't appear to have helped.
Where do I go from here? Is there a way to insert Debugger.Launch() equivalent into a VB6 project? Any help would be appreciated!!
Lifted from robgruen's blog:
If you are using interop to call into a VB6 ActiveX dll or exe and you
need to debug your VB6 project you may find yourself having both
VS.NET and the VB6 IDE open. This can certainly be far from
efficient.
Typically you set your VB6 project to “Wait for the Component to be
created” and you launch your .NET app and then hit breakpoints within
the VB6 component. Well, there’s an easier way to do this. You can
actually debug your VB6 component within VS.NET. Here’s what you need
to do:
1) Build your VB6 project with symbols.In VB6 open up your vbp file
and goto “Project->Properties.” Select the “compile” tab and check
“Compile to Native Code.” Then select the “No Optimization” radio
button and check “Create Symbolic Debug Info.”
This will generate a .PDB (Program Database) file along with your
.EXE. This file contains the debugging information so the VS.NET
debugger can line up source and hit breakpoints, etc. (Make sure you
have binary compatibility on your VB6 dll set or you’ll have to drop
and re-add your reference to the VB6 component in VS.NET.)
2) Open your .NET project in VS.NET.
3) Go to the project properties and select the “Configuration
Properties->Debugging” property page and enable unmanaged debugging.
For VB.NET projects this option is “Unmanaged code debugging” and for
C# is “enable unmanaged debugging.”
4) Select the property page for the solution.
5) Add to the “Debug Source Files” an entry that points to the path
where the source code is for the VB6 component.
6) Add to the “Debug Symbols Files” an entry that points to the folder
where the .PDB file is that was generated in step 1.
7) You should now be able to open your .bas, .cls, .frm, etc. files in
VS.NET and you can put breakpoints in the file. Once you debug the
debugger will stop on those lines of code.
I'm looking for an extension for Visual Studio where in debug mode it's possible to single step through the intermediate language beside C#.
I'm not looking for a solution to debug managed and unmanaged code.
What is your purpose? Is your IL generated by C# compiler or dynamically produced at run time? If the former one, you can use a trick of re-compiling your binary through ilasm.
Compile C# code as you normally would. It does not matter if it is optimized or not, but you have to specify compilation option to produce full PDB symbols.
Use ildasm to convert your binary to .il file. It is option Dump in the menu.
re-compile the .il file to get a new binary (and a new symbols)
ilasm .il [/exe|/dll] /debug
Now when debugging that specific assembly you will see IL code rather than C# code. You will also see a matching lines from original C# file if you select appropriate option in step 2.
For the case of dynamically generated IL, I would simply use WinDbg with SOS extension. It can dump IL and step through it, but it takes a bit to get used to.
Although not strictly a Visual Studio extension as the OP requested, there's now a maybe even better way to do this using dnSpy, a comprehensive, standalone, open-source .NET debugging tool. The tool actually does much more than just debugging; for example it allows direct editing of .NET and native (PEFile) assemblies, de-obfuscating them, browsing and modifying the raw managed and native headers, content, resources, BAML, and metadata, and more that I probably haven't discovered.
For the purposes of the discussion on this page, be sure to check out the IL interpreter section of the dnSpy project. Exactly as requested by the OP, this is the library that implements an IL interpreter for simulating the (pretend) execution of the IL code in parallel with the debugger's (actual) native instruction single-stepping, for the purposes of displaying the state of the (logical) IL execution stack. I believe there's some excellent x86/x64 disassembly rendering built-in to the debugger as well, if needed. Kudos to the developer of this tour-de-force app.
I don't think that an external disassembler is necessary here. When you're debugging in VS 2010 (though not Express) you can right-click on the code window and select "Go To Disassembly" to step through the IL code. Could that be what you're looking for? Read more here
I have a C# Service that is calling a C DLL that was originally written in VC6.
There is a bug in the DLL which I am trying to inspect.
After having a nightmare trying to get debug to work I eventually added the dll to the VS2005 solution containing the C# Service and added the necessary _CRT_SECURE_NO_WARNINGS.
The debug version of the service is registered using 'installutil.exe' tool.
I can get the debugger to break just before the line where the dll is entered via a call to System.Diagnostics.Debugger.Break();.
I found some instruction on the net regarding stepping into debugging unmanaged code, and enabled the 'Enable unmanaged code debugging' check box, I've also tried turning on the Options->Debugging->Native 'Load DLL exports' and 'Enable RPC Debugging' (even though it's not COM). I've also copied the debug dll and .pdb to the same bin directory as the service.
However the unmanaged code is not being stepped into which is what I really need.
UPDATE: I found the Debugging Type in the DLL properties and set it to 'Mixed' as per suggestion on several sites but to no avail.
UPDATE2: My project now emits the debug dll and the pdb to the same directory as the debug service. Still unable to debug the dll.
Try setting the unmanaged code as the startup project. I know it doesn't make sense but I remember this working for a very similar project.
Since the DLL doesn't have an associated executable, when you try to run it will pop up asking what app to run. Browse to your C# app and then you should be good to go.
Happy debugging!
EDIT: it's been a while, but I think the debugging type Mixed is correct
In the end I created a console app and recreated all the prior calls just to make sure the call would act as it did in the actual service with the actual parameters once it got there.
I chronicled my fix and the resultant code at my site.
There is a workaround in Visual Studio 2013. Run the application from cmd line. When System.Diagnostics.Debugger.Break(); is hit, a Visual Studio Just-In-Time Debugger window should pop out. Check "Manually choose the debugging engines.", click "Yes" and ensure that "Native" engine is checked. Click "OK". Now you should be able to step into the native code as if you would by running the code from within VS.