I have an EXE application running in debug mode that loads a DLL at runtime.
When I load the dll it automatically loads the dll's debug symbols for it.
But when I call FreeLibrary() on the dll the symbols won't get unloaded.
That is a problem for me because I use cl.exe to rebuild the DLL while the EXE is running so it needs to be freed and unloaded before I rebuild it.
here is the visual studio runtime debug console output when I load and unload the DLL
'Editor.exe' (Win32): Loaded GameAssembly.dll'. Symbols loaded. <--- automatically loads the symbols when I load the dll
'Editor.exe' (Win32): Unloaded GameAssembly.dll' <--- Dosen't unload the symbols (I know so because when I try to rebuild the dll I get the error (LNK1201 error writing to program database 'GameAssembly.pdb'; check for insufficient disk space, invalid path, or insufficient privilege)
and the functions I use to load and free the dll:
m_DLL = LoadLibraryA("GameAssembly.dll");
FreeLibrary((HMODULE)m_DLL);
now I want a way to unload the symbols when I free the dll, Any idea on how it's done ?
The symbols are not loaded in the app itself, they are loaded in Visual Studio's debugger. The good news is that what you are trying to do works just fine as long as you are not debugging the application.
Unfortunately, there is no way to unload symbols from a debugging session (as far as I know).
One way to fix this would be to tell Visual Studio to simply not load those symbols in the first place. You can do that from the modules window. However, this will prevent you from debugging GameAssembly.dll.
So the only alternative is to not be debugging when you rebuild/reload the dll. To do this, you have to create multiple debugging sessions for a single run of your app. Here's how you go about it
Start debugging the application as you normally would.
When you want to rebuild the dll:
Unload the dll
Detach the debugger by using Debug -> Detach All
Rebuild the DLL
Restart debugging the app by using Debug -> Attach to process
Reload the DLL
The order of the steps can be swapped around a bit, of course. As long as you detach before rebuilding, and don't reload the dll until after the build is done, you should be ok.
I'm making a dll for python using c++ and importing functions using ctypes library.
I know that to do remote debugging you go to Debug -> Attach to Process.
I put a breakpoint in python code before imported function is called, but I don't know what process to attach to. I tried attaching to python.exe, but that didn't work.
What process should I attach to or do I need to do remote debugging differently and if so then how?
Thanks
The process which need to be attached to is the process that needs to call the dll. If you want to remote debug dll, I suggest that you could refer to this link about Remote Debugging a C++ Project in Visual Studio. Also, you could refer to this link about Debug DLLs in Visual Studio.
I suggest that you could look in the modules windows. There are several situations:
1.No Symbols have been loaded for this document
Go to the Modules window (Debug > Windows > Modules) and check whether your module is loaded.
If your module is loaded, check the Symbol Status column to see
whether symbols have been loaded.
a.If symbols are not loaded, check the symbol status to diagnose the issue. From the context menu on a module in the Modules window, click Symbol Load Information... to see where the debugger looked to try and load symbols. For more information about loading symbols, see Specify Symbol (.pdb) and Source Files.
b.If symbols are loaded, the PDB does not contain information about your source files. These are a few possible causes:
If your source files were recently added, confirm that an up-to-date version of the module is being loaded.
It is possible to create stripped PDBs using the /PDBSTRIPPED linker option. Stripped PDBs do not contain source file information. Confirm you are working with a full PDB and not a stripped PDB.
The PDB file is partially corrupted. Delete the file and perform a clean build of the module to try to resolve the issue.
If your module is not loaded, check the following to find the cause:
a.Confirm that you are debugging the right process.
b.Check to see that you are debugging the right kind of code. You can find out what type of code the debugger is configured to debug in the Processes window (Debug > Windows > Processes). For example, if you are trying to debug C# code, confirm that your debugger is configured for the appropriate type and version of .NET (for example, Managed (v4*) versus Managed (v2*/v3*) versus Managed (CoreCLR)).
2.… the current source code is different from the version built into...
You could go to Debug > Options and Settings. On the Debugging/General page, clear the Require source files that exactly match the original version option. Make sure to reenable this option when you are finished debugging.
In addition, it may be that the dll has not been loaded into the .exe. You could set Properties->Debugging->Working Directory.
I have a dll built from mixed code in VS 2012. This dll is loaded from a .exe built in native C++.
When I debug the dll (via F5 from VS 2012), the breakpoints are not hit. The message is :
No executable code is associated with this line. Possible causes include: preprocessor directives or compiler/linker option
However when I run the exe from Windows explorer then perform "attach to process", all the breakpoints are hit.
I tried changing the debugger type to "Mixed", "Native", "Managed", I also played with debugging options but the results were all the same; except when the debugger type is "managed", the breakpoints seem to be loaded (a filled red circle appears instead of an empty red circle) but are not hit.
Can you please give me an explanation of this strange phenomenon ?
When starting a debugging section with the false debug path ( this can be set in the project properties ) it can happen, that the pdb will not be loaded, because the working directory is not at the executable with the pdb. So no information about the source location is there and the debugger can answer: No executable code is associated with this line.
When starting the application directly the working directory is normally the place where the application is located, the pdb get's loaded breakpoint get's hit.
When debugging the app check if the corresponding pdb get's loaded, just to be sure that everything is right here.
I have to debug multiple dlls each within their own project. There is a parent executable that loads a dll, which serves as a container for the other dlls.
My question is how can I debug the whole 'component' ie: all the dll's involved, using Visual Studio 2005 for C++.
If they're all in the same solution, set a breakpoint in the DLL project where you want to debug, right click on the EXE project, and select Debug > Start new instance.
If they're in separate solutions, open the DLL solution, right click on the project, expand the Configuration Properties node in the tree on the left, select Debugging. Set the Command property to point to the debug build of the EXE in the other project. Then set your breakpoint(s) and hit F5 to start debugging.
Arbitrarily pick one of the DLL projects as the startup project, it doesn't matter which. Right-click + Properties, Debugging. Set the 'Command' setting to the path of a test EXE that will load the DLLs. If you don't have a good one then just write one, might as well add it to the project and make it the startup project.
Pay attention to the Output window while the EXE starts. You'll see notifications for each DLL that gets loaded. As soon as one of the DLLs that's in your solution gets loaded then the debugger jumps in, looks for the .pdb file for the DLL and activates any breakpoints you'd have set in the DLL source code. You cannot debug the DLL unless the EXE loads it.
If that still doesn't enable breakpoints then use Debug + Windows + Modules and locate the DLL in the list. Right-click it and choose Symbol Load Information to find out where the debugger looked for the .pdb file. This doesn't go wrong very often since the DLL contains the path to the .pdb file. The far more typical failure mode is that the EXE simply didn't load the DLL.
I copied an existing project and renamed the folder. Now I get this error when I try to compile the application
debugging information cannot be found or does not match. No symbols loaded.
Do you want to continue debugging ?
If I click yes, it compiles and runs fine. But now I have to deal with that message. Just curious about what I change in the projects properties to get it to stop.
You probably have deactivated the debugging information for your project:
Right click on your project -> Properties
Configuration properties -> Linker -> Debugging
Switch "Generate Debug Info" from No to Yes
Rebuild your project and retry, it should now run without the message :)
The main reason is that you don't have a matching pdb and exe.
Some possible solutions:
You are compiling in release instead of debug
You need to clean/build or rebuild
You don't have your pdb files being generated in the same directory as the exe
You have a mismatching pdb, maybe the copied source is newer than today's date and something isn't building properly.
Try cleaning out all debug object files
You are attaching to a process that you started from a different location from where your build exe and pdb exist
Restart Visual Studio
This happens to me every now and then, while debugging code and making changes it seems like visual studio caches the pdb information and sometimes it gets stuck. Doing a Rebuild solution, deleting the pdb and creating a new one doesn't fix the problem.
Of course I do have the generate debug information on and all that it's needed, specially since this happens while debugging the code several times.
Visual Studio seems to be happy with the in-memory pdb and refuses to update it, regardless of time-stamps or even size changes in the pdb.
The only way to reset this is to exit Visual Studio (the IDE) and restart it again.
In some rare occurrences, the IDE might be still running in the background (process explorer shows it there) and might hold the handle to the file open. You can kill the process before restarting the IDE.
Good Luck
I just encountered this error in VS2012. It is definitely caused by a bug in Visual Studio, which reveals itself in situations when the local PDB file of the main project has the same name as the final PDB file for the entire executable (even if the two are located in different directories!)
Consider this example.
Solution consists of three projects: main, a, and b. main is the top-level project for the executable, while a and b are libraries linked into main.
In all three projects $(IntDir) variable is set to $(SolutionDir)\$(Configuration)\$(ProjectName)\. This means that project main dumps its intermediate files to Debug\main\, project a - to Debug\a\ and so on.
In C/C++ -> Output Files settings all three projects have Program Database File Name value set to $(IntDir)$(TargetName).pdb. This means that project main generates its local PDB file as Debug\main\main.pdb, project b as Debug\b\b.pdb and so on.
Finally, in Linker -> Debugging settings of project main the Generate Program Database File value is set to $(OutDir)$(TargetName).pdb. This means that the global PDB file for the entire executable will be generated as Debug\main.pdb.
Note that in this setup each PDB file is generated in its own, separate directory.
In this setup you will get Debugging information cannot be found or does not match error if you attempt to run the program under the debugger. And if you take a look at the Debug\main.pdb file (which will exist), you will notice that it is exactly the same as Debug\main\main.pdb file! I.e. somehow the local PDB for main managed to overwrite what was supposed to be the global PDB for the final executable. I.e. the debugger is right to complain that the PDB file is "wrong". It is indeed wrong.
Again, in the above setup the final global PDB somehow gets overwritten by local PDB of the top project. I don't know why it happens. It appears to be a bug. (Note that even though these PDB files have the same name, they are generated in different directories, i.e. they should not conflict.)
A workaround that fixes this issue is to give the local PDB of project main a different name. For example, just go to C/C++ -> Output Files for the main project and change Program Database File Name value to $(IntDir)$(TargetName)_local.pdb (or to $(IntDir)12345.pdb if you so desire). This will eliminate the conflict and solve the problem.
Enable PDB creation by:
Right click on MyProject > Properties > Debugging:
C/C++ > General > Debug Information Output = Program Database (/Zi)
Linker > Debugging > Generate Debug Info = Yes (/DEBUG)
Clean MyProject, restart Visual Studio (just to be sure), rebuild MyProject.
The output folder should then contain *.pdb files.
If you debug optimized/release code consider switching off optimization via
C++ > Optimization > Optmization = Disabled (/Od)
I faced the same problem and tried all above mentioned solutions but it couldn't help me.
Then I found a new solution randomly and it worked.
Solution is that,in case you are having many projects in a solution then you should mark any one (specific one which you have to decide) project as a "Set as Startup Project".
Right click on that specific project and click "Set as Startup Project".
It worked for me.
The pdb or Program Database file appears to be missing (basically, the path has changed and can no longer be found by the compiler). See this related post for additional information.
I had a similar problem and the reason was that I had run one of the projects of my solution in a different process and that process couldn't be killed. I didn't think much of it. So when I was building the solution in a separate environment one of the pdb files didn't match so at the end I couldn't load any of the pdb files. I just restarted my computer and that fixed it.
Good luck
Restarting Visual Studio can fix one instance of this problem.
Right click on your project in the solution browser => Clean => Build.
That is if your build generates a .pdb at all (look in your target dir)
If not, you should enable debug by the steps mentioned in other posts
Most probably there are other reasons like .pdb / .exe file mismatch, something were not built / rebuilt, but I had similar case in Visual studio 2013 -
Something to do with virtual inline function - so I suspect.
In my case debugger were jumping in a middle of another C++ function, not the one which was called. Jump was off source code by 11 source code lines, but I cannot explain why much miscalculation happened. By simple rearranging functions I've got rid of this problem.
May be needs more detailed analysis why 11 lines shift happened originally.
Haven't seen this kind of behavior in any other visual studio.
This problem has bothered me for a long time. AnT's anwser is very helpful. The main idea is Don't have any two pdb files have the same name, even they are not in the same directory.
This is my situation: I have tow projects name "FooBar" and "FooBarDll", the first one is an exe, and the second one is a dll. I set both projects Target Name to be "FooBar", so that they will generate "FooBar.exe" and "FooBar.dll" respectively.
Then I set
"General -> Intermediate Directory" to be "$(OutDir)\$(ProjectName)\"
"C/C++ -> Output Files -> Program Database File Name" to be "$(IntDir)$(TargetName).pdb"
"Linker -> Debugging -> Generate Program Database File" to be "$(OutDir)$(TargetName).pdb"
So I get these files:
Debug\FooBar.exe
Debug\FooBar.pdb //C++ pdb
Debug\FooBar\FooBar.pdb //Linker pdb
Debug\FooBar.dll
Debug\FooBar.pdb // C++ pdb again!
Debug\FooBarDll\FooBar.pdb // Linker pdb
My solution is replacing every "TargetName" with "ProjectName", then I will get:
Debug\FooBar.exe
Debug\FooBar.pdb //C++ pdb
Debug\FooBar\FooBar.pdb //Linker pdb
Debug\FooBar.dll
Debug\FooBarDll.pdb // C++ pdb
Debug\FooBarDll\FooBarDll.pdb // Linker pdb
Then there is no conflict!
Give C/C++ pdb a suffix may be better, like: "C/C++ -> Output Files -> Program Database File Name" to be "$(IntDir)$(ProjectName)_C.pdb"
I had the same issue, and this link helped me solved the problem, by rename "symsrv.no" to "symsrv.yes" in VS IDE folder.
Curious, it happens to me that I needed to change the folder name from:
...\Custom Librarry (MyDll.dll(
to
...\Custom Librarry (MyDll.dll)
just by closing the parenthesis it worked !