I have a native C Dll that calls 'LoadLibrary' to load another Dll that has the /clr flag turned on. I then use 'GetProcAddress' to get a function and call it on dynamically loaded dll. I would like to step into the dynamic library in the debugger, but the symbols never load. Any idea?
And I should have said I'm using Visual Studio 2008.
Update: Thanks to some tips below, I changed the project debugging to Mixed. It didn't work, but I think I know why. I am developing an addin to an existing application. The app I'm connecting to starts one exe then it starts another. So I have to use "Attach to process" to fire up the debugger. My guess is launching the debugger that way will default to "Auto". Is there a way to change the default behavior of VS to use "Mixed" debugging?
This is from VS2008, but if I remember correctly VS2005 was similar. In the native project's properties, under "Configuration Properties->Debugging" there is a "Debugger Type" which is set to "Auto" by default. You'll need to change it to "Mixed", because VS isn't smart enough to realize you need managed debugging
I've had mixed experiences with doing similar things like this in VisualStudio. You might consider using ProcMon to see where VisualStudio is looking for the PDB file. Alternatively, you might try using WinDbg. It seems to do better at loading symbols and if it doesn't, you can explicitly load them yourself. Using WinDbg involves riding a steep learning curve, but if you're burning time right now, isn't it worth it?
You can also run the exe on its own and from the source of the managed dll, attach to the process to debug it.
Modify the mixed-mode dll to throw a CLR exception where it enters the first code you're interested in debugging. This should give you an opportunity to launch the managed debugger.
In VS2005, there are per-project options to enable native and CLR debuggers separately. You might need to enable the CLR debugger for the native dll project from which you start the debugger.
Related
Environment: I have a .NET 4.0 solution that references some Visual C++ projects. Visual Studio 2010.
If I build my solution and run the resulting .exe right from the bin directory, I can reproduce my bug. But if I run it hitting the "play" button in Visual Studio (or if I run the process and attach to it) I can step through the code, and everything works as normal.
For reference, the problem I'm getting is an Access Violation which is most definitely happening the C++ code.
But more broadly, I'm wondering what other reasons there might be that attaching a debugger to a process "fixes" the issue.
MS VS is working like a sandbox. When you are starting app in that sandbox, your program inherits all settings from solution properties (or just VS settings). Make sure, all your options provided for the environment are correct. If that wont solve the problem, please double check those settings and think what can prevent access violation and uncheck/check it.
If you are using external DLL, those from you system and those from IDE may have different version. They, of course, may work in both cases, but also may cause problem like access violation or subcribent out of range, depending what is changed inside those dlls.
If its Windows app, try enabling/disabling LargeAddressAware.
If you are compiling stuff for another machine with different OS, it may happen very often due to changes in memory handling by native OS. Memory can sometimes be multi-blocked, extremely fragmented or even multi-deviced, so compile your program only with compilation especially made for targeted OS/machine
debug mode uses assert() and other stuff directly linked to debugging. If something is wrong in debugging and not in release, it means that it is acceptable by machine but not by debugging insertions. In that case you are screwed but if its not appear to be problem in other debugger, well... problem solved, its debugger issue, espeially if release without debugging options is working.
most tiring method - try to pinpoint access violation address and see inside memory windows to what are you referring.
in other cases, supply us with snippet, so we can tell something more!
#Matt this cant be heap problem, it can happen but its extremely rare.
#Huytard its wont happen, without linked dll's program should't even start.
The correct and short answer. Run Windows Updates.
The correct and long answer.
It turns out my build machine hasn't been updated in a while and was using an outdated version of Visual C++ compiler. There was a bug in the compiler for .NET 4 where static constructors were not getting called first before any other types of constructors (only in Release Mode).
But here's the kicker!
If you run the process in the Visual Studio debugger OR you attach to a remote process. The static constructors DO get called first like they are supposed to! (Hence making the issue completely un-reproducible in a debugging environment -- Even in Release mode) I found the issue by placing message boxes all over the place to determine the code path.
http://connect.microsoft.com/VisualStudio/feedback/details/611716/c-cli-class-static-constructor-not-called-in-release-build
Running the green "play" button will use the IDE's environment
Executing from the directory will use the default environment
My guess is that there are probably some DLL's or dependencies that need to be added (directory paths) to your %PATH% environment variable.
Once you identify the dependencies and double check or something with dependency walker - you can set them in a batch script and then call your application.
For example:
#echo off
set PATH=%PATH%;C:\myLibs
call MyApp.exe
I feel like this is a stupid question, but I can't seem to figure out the answer. I've currently got a C++ application that's loading & utilizing a DLL (I compiled both the application & the DLL with VS 2010). I'm positive it's using the DLL, because a) if I rename the DLL, I get a not found exception, and b) it's displaying output that only comes from (and I can change it to see the output change) inside the DLL.
My problem is that in Visual Studio's Modules window while debugging, the DLL does not appear to be loaded. Because of this, obviously its got no symbols and I can't set breakpoints... But this doesn't make any sense to me as it's clearly using the DLL.
I've seen several other similar questions, and the answer has generally been too look at whether the code is native, managed, or mixed, and set the "Attach to Process" field accordingly. I've tried all the options there, and made sure my Debugger Type is set to "Mixed" (though I've tried it with Native & Managed as well, just to verify none of these solve the issue).
Does anyone have any suggestions?
Thanks in advance!
This happened to me and I found the project->properties->Debug page and clicked the box to Enable native code debugging. I was doing a C# project accessing a C++ / native dll
budward
I have some ideas:
check output windows it the DLL symbols are missing.
Make sure dllname.pdb file exist beside the DLL
make sure visual studio solution has two projects (EXE,DLL) projects
switch to DEBUG mode instead of RELEASE mode.
run process explorer (download it from MS) and check the path of the DLL that is bonded to the EXE in runtime.
Finally the ultimate solution:
Open Process Explorer and search for your DLL name.
Find which EXE is using it.
Goto VS and attach your debugger to that EXE.
I hope any of those fix your issue
I'm developing a plugin for InDesign CS5.5. And when developing a plugin you can't really debug if you don't have the debug version of the program you're developing for(in my case, indesign).
I tried to get the debug version from adobe with no success. A lot of bureaucracy.
So my question is: Is there a way to attach a debugger(or something else) so I can see where the code is going to?
I'm really tired of typing "MessageBox".
Thanks in advance.
For indesign plugin development c++ is used by the way.
If your plug-in is a dll that's loaded dynamically, you can attach Visual Studio to the process, set breakpoints, and step into your dll's code. To attach to an existing process, just go to debug -> attach to existing process, or try the shortcut Ctrl+Alp+P IIRC.
sometimes I have to debug an application that was written with Borland C++ Builder. This application loads dlls compiled with Visual C++. Is there a debugger that can debug both parts of the application? Currently I have to decide - either I can easily set break points and see the source in Visual Studio or I have to start Borland C++, but I can't work with the source from the Visual-Studio compiled dll.
thank you for your help,
Tobias
You could try OllyDbg - version 1.x does not seem to support the latest Win version but there is also the 2.0 although it's still in alpha state(haven't tried myself that one yet).
EDIT - clarification:
Source debugging OllyDbg reads debugging information in Borland and
Microsoft formats. This information includes source code and names of
functions, labels, global and static variables. Support for dynamical
(stack) variables and structures is very limited.
The above is take from here.
UPDATE:
I'm not familiar with the Borland C++ Builder but at this link you can find some articles explaining how to deal with some interoperability issues between Borland and MS that might be of help.
if both parts built using ulink linker and have debug info you could try cdb32 debugger (from the ulink linker author)
cdb32 is still in its alpha stage though and I personally never tried such "mixed" debugging
Have you tried loading the DLL code in VS, loading the app code in BCB, and having both debuggers attached to the same running process at the same time? Not sure if Windows will allow that, but it might be worth a try.
I suspect there is no perfect answer to your question, you are going to have to compromise in some way, as I'm sure you are already doing.
I have a similar problem to yours at work. The applications that I work on are written in Python instead of Borland C++, but like your situation, these apps rely on a rather large Visual Studio compiled DLL for some functions.
My method of debugging these applications involves a combination of two debugging strategies: the use of an interactive debugger and the so called "printf" debugging technique.
What I basically do is pick one of the two areas as my main debug focus, and that determines my debugging approach:
If for a given situation I decide that I need to debug the DLL with greater detail, then I work with the VS debugger. I set the executable to run in the DLL project as my python script and that enables full debugging of the DLL code. If I need debugging support from the Python side, then I add print statements. If I need a breakpoint on the Python side to inspect some values, I just print all those values and immediately after call a C++ function that does nothing, but that has a breakpoint set in VS.
When I need to concentrate more on the Python side more I use a Python interactive debugger, but I have VS with the DLL project loaded on the side so that I can quickly add any necessary printfs on the DLL and recompile, so essentially the reverse of the above.
I know it's not the answer you expect, but it is a decent solution in my opinion.
It looks that it is possible to convert the debugging information generated by C++ Builder to a format understood by WinDbg (link to discussion). If so you could use it to debug both parts of your application (I haven't tried this though).
you can convert the .map files to Microsoft's debug file format
http://code.google.com/p/map2dbg/
now you can use Windebug; there is also a tool mentioned to convert to pdb format, so you could try the vc++ debugger
I'm a hobbyist developer and have a background with Java (IDE of choice was Eclipse). I'm using Visual Studio Express 2010 and wanting to learn C++.
Few questions:
I create a "HelloWorld" in C++ and compiles/runs in VS/Windows. When I try to compile it under Linux/GCC, it obviously throws tons of errors. Default windows console project includes windows specific files; but if just create an "Empty Project" it throws tons of linker/build errors. What's the best practices here to keep my code portable?
Why is it creating 47 files for 8 lines of code?
How do you format code? You can do Edit->Format Selection, but the hotkeys don't work?
How do I output to VS's 'Output' Window? ( like eclipse does when you run a console java app )
It keeps reverting my "Project Location" to my "home directory" every time I restart. How do you change it? Is it a bug? Because it's Express edition?
Is there a way to keep it from switching to Debug view when it runs?
I create a "HelloWorld" in C++ and
compiles/runs in VS/Windows. When I
try to compile it under Linux/GCC, it
obviously throws tons of errors.
Default windows console project
includes windows specific files; but
if just create an "Empty Project" it
throws tons of linker/build errors.
What's the best practices here to keep
my code portable?
For portable code, avoid VS wizards entirely. Use Make/NMake if you're starting with rocks and sticks, or the portable build system of your preference (Ant, CMake, etc.) Some of these will spit out a VS solution/project file for you to use.
Why is it creating 47 files for 8
lines of code?
Wizards are magical like that.
How do you format code? You can do
Edit->Format Selection, but the
hotkeys don't work?
Ctrl-K Ctrl-F (under Edit, Advanced)
How do I output to VS's 'Output'
Window? ( like eclipse does when you
run a console java app )
Lookup OutputDebugString() for the debug window. Output window should get all cout/cerr output.
It keeps reverting my "Project
Location" to my "home directory" every
time I restart. How do you change it?
Is it a bug? Because it's Express
edition?
Probably hidden in options somewhere - don't know that one, sorry.
Is there a way to keep it from
switching to Debug view when it runs?
Launch using Ctrl+F5 to run without the debugger attached.
Have fun!
I create a "HelloWorld" in C++ and compiles/runs in VS/Windows. When I try to compile it under Linux/GCC, it obviously throws tons of errors. Default windows console project includes windows specific files; but if just create an "Empty Project" it throws tons of linker/build errors. What's the best practices here to keep my code portable?
It's fairly difficult to keep your code truly portable if you're writing Windows applications. Standard C++ will obviously work on either platform, but Linux can't run Windows applications, and vice versa. Remember that console applications are also considered Windows applications. They're not any more "pure" just because they are text-based, rather than graphical. Windows applications have their own entry point, different from the standard main function found in ANSI C++ (technically, main is still there, but it's hidden and called internally by the Windows libraries).
The best thing to do is not to link to any of the Windows headers. Unfortunately, you won't be very satisfied with the results. About all that you'll be able to generate is library code. You can't get a UI on the screen unless you use the Windows functions to do it.
An "Empty Project" is just what it says—empty. I assume the build errors are because you're trying to call functions that aren't defined anywhere. You'll find that you need to include windows.h to get off the ground, which instantly makes your code non-portable.
Why is it creating 47 files for 8 lines of code?
This is obviously an exaggeration; none of the wizards produce anywhere near that many code files. Especially not the "Empty Project", which doesn't create any at all.
A Win32 console application includes the following 5 files:
stdafx.h and stdafx.cpp — these files are used to enable "precompiled headers", meaning that Visual Studio will compile all of your headers once, and only recompile them when they change, rather than recompiling them each time you build the project. This used to provide enormous speed boosts, and still does on large projects. You probably don't need or care about this for small projects, but it's not a bad idea to get familiar with their usage if you're going to be developing in Visual Studio.
A targetver.h file, whose only purpose is to specify the earliest version of Windows that you want your application to run on. This is necessary because later versions of Windows add additional functionality that wasn't available in previous versions. Your app won't run if you link to functions or libraries that don't exist. Set this up once and then forget about it.
A <projectname>.cpp file, which is the implementation code for your application. This is pretty standard stuff—it includes the _tmain function, which is the entry point for a console app.
A ReadMe.txt file, which you can immediately delete. It contains some introductory information and describes the files that have been added to your project. (Yes, reading this yourself could have answered this question.)
A Win32 application would have a few more files, but most of the same ones as well. In particular, you'll see a resource file (with the extension .rc) that contains the icons, dialogs, bitmaps, cursors, etc. used in your program.
If you don't like this structure, you can either forgo the use of a wizard, or modify it yourself. There's nothing set in stone about it.
How do you format code? You can do Edit->Format Selection, but the hotkeys don't work?
Formatting code works fine. I'm not sure why people are telling you that Visual Studio doesn't support this, or that you'll need a third-party plug-in. There's no "Format Document" command as there is in C#, but the "Format Selection" command works just fine. The only difference is, you have to select something in order for it to be enabled.
The default keyboard extension for that command is CtrlK, Ctrl+F. It also works fine, right out of the box. My typical workflow is to hit Ctrl+A first to select all.
How do I output to VS's 'Output' Window? ( like eclipse does when you run a console java app )
I don't know what Eclipse does, nor do I know anything about Java. What do you want this to do? When and what things do you want to get written to the "Output" window? A console application will run in a console window, not in the "Output" window. That's not what it's for.
It's intended for debugging purposes. The OutputDebugString function is one way of utilizing it. The output of the standard cerr keyword should be automatically redirected to the "Output" window.
It keeps reverting my "Project Location" to my "home directory" every time I restart. How do you change it? Is it a bug? Because it's Express edition?
This isn't a bug, it's a feature. Visual Studio is designed for working with projects and solutions, not one-off code files. So by default, it prompts you to specify a project folder, a location to store your files. And what better place for the default location than your home folder?
If you don't like that location, you can change it. Under the "Tools" menu, select "Options". Expand the "Projects and Solutions" category, and click the "General" item. Then, change the path of the "Projects location" (the top textbox). Couldn't get much simpler than that.
Is there a way to keep it from switching to Debug view when it runs?
I frankly don't understand how this question makes any sense at all. When you run an application with the debugger attached, Visual Studio switches to a different window layout specifically optimized for debugging. I just answered a similar question. The upshot is that there's no way of telling Visual Studio to use the same window layout for both design and debug view, but I also can't imagine why you'd want to, either. Different things are useful, depending on what you're currently doing.
The two window layouts are customizable, and your changes are remembered. I've customized mine heavily from the defaults; it's very likely that your tastes vary as well. There are lots of great features, like the "Locals" window, which shows a listing of all the values of the local variables in scope at the point where you break into your program's execution.
Also remember that the default "Debug" and "Release" build configurations have nothing to do with whether or not Visual Studio automatically attaches the debugger to your application's process. If you want to start your app without the debugger attached, select "Start without Debugging" from the Debug menu, or press Ctrl+F5. There are lots of side effects to this though, and it's probably not what you wanted. Without the debugger attached, you lose most of what Visual Studio provides to you as an IDE. You might as well just run the app from Windows Explorer without even launching VS.
Finally, if you prefer Eclipse (or at least are already accustomed to its nuances and prefer not to learn Visual Studio's), you can still use it for C++ development. Download it here.
If you're just wanting to learn C++ and you don't necessarily care about the platform, I would probably avoid using Visual Studio to start with. Visual Studio provides some functionality for managing projects and builds, but honestly, I think you're better off learning how to manage code files and use the compiler on the command line first, then working up from there.
If you're on Windows, I'd recommend installing Cygwin and getting the GNU compiler tools through the Cygwin setup utility (gcc or g++).
This is a bit of an opinionated answer, but my experience with C++ on Windows leads me to believe that you'd be better served trying to learn C++ from more of a unix-like angle. Windows C++ adds a whole layer of crap that will just confuse you when you're getting started.