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".
Related
I have two VS solutions. Solution A_sol is C++/C# projects. Solution B_sol has project B_proj that is C# wrapper around C++ *.dll generated by B_proj project in A_sol.
How do I debug A_proj from B_proj ?
UPDATE: one of the projects in B_sol is an executable.
How do I debug A_proj from B_proj ?
If I understood you correctly, A_proj is a C++ project. Below I will give my advice based on this assumption.
Note that it doesn't really matter from which project/solution you start debugging as long as you have the debug info (in other words, for C++ projects - if Visual Studio is able to pick up PDB's).
So you may either run your executable from the solution, or, as suggested by #hoodaticus in his answer, attach to the process which is already running. Whether your project is executable or not, you will be able to attach to it as long as:
DLL is loaded into that process
You have the PDB file that matches the DLL (generated during the build)
So I'll just repeat the same advice
In the other project, do Debug > Attach to Process > pick your process
from the list.
but I'll add that you have to pay attention to select "Debug these code types -> Native" for the process that contains your C++ dll. This part is often missed and confuses people, taking some time to discover (personally, I often get into it)
Hope that helps.
Run the process you want to debug outside the debugger.
In the other project, do Debug > Attach to Process > pick your process from the list.
To be able to debug by pressing F5 (rather than having to pick your process each time),
Right-click the startup project (the EXE) and choose Properties
In the Debug tab, select Enable native code debugging
The above steps are from this tutorial: https://learn.microsoft.com/en-us/visualstudio/debugger/how-to-debug-managed-and-native-code?view=vs-2019
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
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 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.
If I have a DLL (that was built in release-mode) and the corresponding PDB file, is it possible to debug (step-into) classes/methods contained in that DLL?
If so, what are the required steps/configuration (e.g. where to put the PDB file)?
Edit:
If have the PDB file in the same place as the DLL (in the bin/debug directory of a simple console test application). I can see that the symbols for the DLL are loaded (in the Output window and also in the Modules window), but still I cannot step into the methods of that DLL.
Could this be the result of compiler optimizations (as described by Michael in his answer)?
The pdb is usually (for me at least) detected if it is next to the dll (like with the intellisense xml files).
Alternatively; you'll need a break point after the module has loaded...
At the break-point, bring up the "Modules" window (Ctrl+D,M - or Debug->Windows->Modules). Right click on your dll "Load symbols from", "Symbol path", etc.
Yes, you can debug release code with a PDB. There are some pitfalls however with debugging optimized code, more info here and here.
Your PDB just needs to be in a place that the debugger can find it - for local debugging same directory as the dll is usually easiest. Otherwise, put it in some place that the debugger can find it, and point the debugger to that place with the symbol path.
I finally found what cause the problems debugging a DLL that was built in release configuration:
First of all, it basically works as expected. Which means, if I have a DLL built in release-configuration plus the corresponding PDB file, then I can debug the classes/methods contained in that DLL.
When I first tried this, I unfortunately tried to step into methods of a class which has the DebuggerStepThroughAttribute, e.g:
[System.Diagnostics.DebuggerStepThrough]
public class MyClass {
public void Test() { ... }
}
In that case, it is of course not possible to step into the method from the debugger (as expected/intended).
So everything works as intended. Thanks a lot for your answers.
Debugging a release build is typically much harder that debugging a debug version. In general you'll need some understanding of x86 assembler and you'll likely spend some time looking at the disassembly window. This tends to be the only way to figure out what line of code you are really on since in a release build with optimizations on the compiler may do significant inlining and instruction reordering. In addition I find the debugger frequently fails to correctly report values of variables. If you need to know a variable's value and you are not sure the debugger is correct, go into the disassembly window and find the memory location or register it is located in.
The pdb files can be stored in a Symbol Server. Check out Setting up a Symbol Server for a good tutorial. Every product we build on a build machine publishes the symbols to our symbol server, so we can always debug any crash dumps we receive from WinQual.