The basic interface while debugging a basic c++ file with gdb in vscode editor is something like this:
notice the line no. 133 , it contains a function call whose value is not stored in any variable, and it results into a file path somewhere in the user's directory. How do we analyze such return values?
My first question is:
Is there a way to watch this return value in vscode without having to store the return value in any variable?
Secondly,
If it's not possible to see it in vscode, is there a way to do that in the gdb debugger? Since vscode seems to be using the gdb internally, maybe there's a way to setup the settings.json using gdb's flags? If anyone knows, please do mention it.
Related
I have written a Fortran code for being compiled as a '*.DLL' file.
The program which reads that file is a Finite Elements Method software named Plaxis, I already achieved to generate the '*.DLL' file in Visual Studio and Plaxis recognizes my model but the model does not work fine.
I would like to evaluate all the variables involved in my code and the procedure that Plaxis is using to read them, but when I use commands like "write(*,*) 'variable'" Plaxis does not show me what I asked in the source code.
Probably you want to open a file and write to that for debug logging, because presumably Plaxis doesn't run with standard output connected to anything useful. Or maybe it would if you just ran Plaxis from a command line window?
It's not going to create a dialog box for you.
But anyway, another option would might be attach to Plaxis with a debugger, and set a breakpoint in a function in your DLL. Then you can single-step your code as called by Plaxis.
Or you can write your own test callers and write unit tests for your functions, making them easy to debug. This could work well if your function just gets an array + size as args.
If instead it passes some wrapped object that you need to call special functions to deal with, then maybe make another version of your function that does just take an array so you can call it from a simple test caller.
I remember seeing somewhere that you can specify which dll to get the address of symbols so that one can use that variable in the watch window. I can't for the life of me remember where I saw this. The best that I can come up with is Format Specifiers in C++.
The reason I want this is so that I can see the visibility status of a window and MSVS keeps saying that identifier "IsWindowVisible" is undefined.
I was trying to use something like the following in the watch window:
::IsWindowVisible(m_hWnd),user32.dll
Using:
this->IsWindowVisible()
results in Function CWnd::IsWindowVisible has no address, possibly due to compiler optimizations. which is why I'm trying to use the win32 call. Ideas?
http://msdn.microsoft.com/en-nz/library/y2t7ahxk.aspx
Haven't tried it, but it seems to me that IsWindowVisible(m_hWnd) should work, or maybe IsWindowVisible(this->m_hWnd).
I'm using windbg to debug an Windows executable. I want to know how I can see arguments passed to any function using WinDBG.
For example If I wanna know the parameters passed to function Kernel32!CreatefileA using Immunity Debugger or Olly debugger I will set a break point at entry point of Kernel32!CreatefileA.
Now in bottom right corner of debugger window i could see nicely what are the parameters are getting passed to Kernel32!CreatefileA by the program. Like this screen shot.
So my question is how how can I get a similar view of passed parameters using WinDBG.Is thre any way??
Is there any plugin which can represent the stack visually like olly or immunity??
Thanks in Advance
If you have private symbols, dv will show you locals and arguments. There is also a "Locals" window that can be opened with Alt+3 if you prefer to use the GUI.
If symbols are not available, it is not quite so easy. You can start with kv to see raw arguments and calling convention. Once you know the calling convention, you know where arguments are stored (stack and/or registers), and it is a matter of deciphering their layout in memory.
I'm using XCode to debug some code. Specifically, the code that I'm debugging exposes a float[][] as float**. I am unable to change this syntax, but I'm not certain it would help anyway.
After including a relevant breakpoint, I want to view the contents of the array in the Variables view of the debugger?
When I double-click on the variable in the list of Autos, I see that I can add a Summary Format which seems deceivingly like it might help, but for the life of me, I can't figure out how to use it!
In conclusion, how do I use the Variables View to see the contents of my array of arrays of this primitive type without resorting to typing commands directly to GDB (which, I believe, can also perform this function)?
I'm currently in a Python interactive interpreter session. I have a function that I know is doing something funky, so I want to step through it in a debugger session. I know the file name and line number of the function.
Is there any way for me to now set a breakpoint in the start of that function, then run it and step through it? Without having to open an editor, locate the file, locate the function, manually insert import pdb; pdb.set_trace(), saving the file, then go back to the interpreter, reload the module the function came from and running it? Not to mention that if I forgot to remove the pdb trace that'd spell trouble later.
Summarizing the question: If I'm in a normal Python interpreter session (or iPython), is it possible to set a breakpoint somewhere and start debugging, without having to actually edit in the code pdb.set_trace() somewhere?
I can't believe I missed this, but I just glanced over the pdb documentation a second time and realized that all the run* functions do pretty much exactly what I want. They don't let me set a specific line as a breakpoint, but I can pass the function and the arguments I want to use, and it will break on the first line of the function:
import pdb
pdb.runcall(my_wonky_function, "arg1", "arg2", *myargs)
Well actually it broke at a mystical location called "EOF":
(Pdb) list
[EOF]
and I had to step twice before I got to the first line of the function, but that's hardly a problem.