I'm getting this weird error on some stuff I've been using for quite a while. It may be a new thing in Visual Studio 2010 but I'm not sure.
I'm trying to call a unamanged function written in C++ from C#.
From what I've read on the internet and the error message itself it's got something to do with the fact that the signature in my C# file is not the same as the one from C++ but I really can't see it.
First of all this is my unamanged function below:
TEngine GCreateEngine(int width,int height,int depth,int deviceType);
And here is my function in C#:
[DllImport("Engine.dll", EntryPoint = "GCreateEngine", CallingConvention = CallingConvention.StdCall)]
public static extern IntPtr CreateEngine(int width,int height,int depth,int device);
When I debug into C++ I see all arguments just fine so thus I can only think it's got something to do with transforming from TEngine (which is a pointer to a class named CEngine) to IntPtr. I've used this before in VS2008 with no problem.
I had a _cdecl c++ dll that I called without any trouble from Visual Studio 2008, and then the identical code in Visual Studio 2010 would not work. I got the same PInvoke ... has unbalanced the stack error as well.
The solution for me was to specify the calling convention in the DllImport(...) attribute:
From:
[DllImport(CudaLibDir)]
To:
[DllImport(CudaLibDir, CallingConvention = CallingConvention.Cdecl)]
I guess they changed the default calling convention for DLLImport between .NET 3.5 and .NET 4.0?
It could also be that in the .NET Framework version 3.5, the pInvokeStackImbalance MDA is disabled by default. Under 4.0 (or maybe VS2010) it is enabled by default.
Yes. Technically, the code was always wrong, and previous versions of
the framework silently corrected it.
To quote the .NET Framework 4 Migration Issues document: "To improve
performance in interoperability with unmanaged code, incorrect calling
conventions in a platform invoke now cause the application to fail. In
previous versions, the marshaling layer resolved these errors up the
stack... If you have binaries that cannot be updated, you can include
the <NetFx40_PInvokeStackResilience> element in your application's configuration file to enable calling
errors to be resolved up the stack as in earlier versions. However,
this may affect the performance of your application."
An easy way to fix this is to specify the calling convention and make sure it is the same as in the DLL. A __declspec(dllexport) should yield a cdecl format.
[DllImport("foo.dll", CallingConvention = CallingConvention.Cdecl)]
Maybe the problem lies in the calling convention. Are you sure the unmanaged function was compiled as stdcall and not something else ( i would guess fastcall ) ?
Use the following code, if say your DLL has the name MyDLL.dll and you want to use the function MyFunction within the Dll
[DllImport("MyDLL.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.Cdecl)]
public static extern void MyFunction();
this worked for me.
In my case (VB 2010 and DLL compiled with Intel Fortran 2011 XE) the problem exists when my application targets .NET Framework 4. If I change targeted framework to version 3.5, then everything works fine as expected.
So, I would guess the reason is something introduced in .Net Framework 4 but I have no idea at the moment which one
Update: The problem was solved by recompiling Fortran DLL and explicitly specifying STDCALL as calling convention for export names in the DLL.
Related
I have been using a pre-compiled DLL in some software for a few years now. Now that software required a new feature so I dusted off my project and made my changes. It was originally built for .NET 4.0, but since that is unsupported I switched to .NET 4.8, trying to keep the same major version to avoid too many differences.
My original code I did not specify a calling convention so I assume StdCall was used, but when I went to run it I got a "PInvoke has left the stack unbalanced" exception. I changed all call types to Cdecl, which resolved that error. I think this was correct to do, but it could be related to my problem still.
Now one particular method is called, (one that is supposed to give a human readable reason for an error code) the application closes. If I try to execute the method in the watch window I get an error that the target process exited with a seemingly random code (-1073740940) which does not seem like the intention of the DLL.
Since the DLL hasn't changed, I assume something about dllimport has that is causing this issue. The documentation for the DLL denotes a single long input and a char* return type which I assume means it is an ANSI string, but I've tried multiple return marshal types. This is what I think is the most correct DLLImport I've tried (the DLL I'm using is not public so I've changed the DLL name and entry point).:
[DllImport("provided.dll", EntryPoint = "getErrorString", CallingConvention = CallingConvention.Cdecl)]
[return: MarshalAs(UnmanagedType.LPStr)]
public static extern string GetDLLErrorString(long errorCode);
I'm running a c# application on mac using mono and xamarin as the IDE.
In my main method i have:
[DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true, ExactSpelling=false)]
public static extern bool SetEnvironmentVariable(string lpName, string lpValue);
and then when i call it:
SetEnvironmentVariable("PATH", path);
i get an EntryPointNotFoundException
System.EntryPointNotFoundException: SetEnvironmentVariable
at at (wrapper managed-to-native) EICService.Program:SetEnvironmentVariable (string,string)
at EICService.Program.Main (System.String[] rawArgs) [0x00031] in (*my path*)/Program.cs:34
now i know that calling kernel32.dll on mac is a problem, but i assume that it is finding it or whatever mono has as a replacement for it because if i put some dummy dll file name there i get a dll not found error.
i'm very much a noob with c#, but this code runs on windows, we just want to have it running on unix.
any ideas?
This is a Windows API function. It simply does not exist on a Mac. Hence the error.
You don't need to p/invoke this function to set a variable in the process environment. You can use the native .net functionality. That is Environment.SetEnvironmentVariable.
What's more, you should be doing exactly the same on Windows. It's never a good idea to p/invoke a native function to perform functionality offered by the .net runtime libraries.
Last week I stumbled upon a problem and I'm not sure how to solve it. I already spent a whole day to try to solve it alone.
I have an unmanaged DLL that worked fine in my C# code on a Windows XP (32 bit) System. When I try to run this C# code on a newer System (for example Windows 7 (64 bit) it doesn't work anymore.
This is the code
[DllImport("MyTest.dll")]
[return: MarshalAs(UnmanagedType.LPStr)]
public static extern String DoSomething();
As I said this works fine on my Windows XP System but doesn't work on my Windows 7 System. When I try to run this code on my Windows 7 System I get the following Exception (translated into English)
The DLL "MyTest.dll": Recurrence too deep, Stackoverflow. (Exception from HRESULT: 0x800703E9) can not be loaded.
I'm guessing the problem is because of this:
Load 32bit DLL library in 64bit application
How to call win32 dll in windows 7
I'm just not sure about it because when I search for my exception in combination with DLLImport I can't find anything.
If this is really the problem what would be the best solution?
You could check:
unmanaged dll dependencies with dependency walker. There might be missing c++ redistributable. Look for MSVCR{xxx}.dll where {xxx} specifies version of the redistributable.
compilation settings of managed application that in the end loads unmanaged dll (Any CPU, x86 or x64). Might be that managed application is set to Any CPU but unmanaged application is x86 and therefore load of unmanaged dll fails.
installed .NET frameworks on windows xp and windows 7. The problem might be different patches applied on .NET frameworks but this is the least likely to be your problem.
I solved the problem like this:
[DllImport("MyTest.dll", CharSet = CharSet.Ansi)]
private static extern IntPtr DoSomething();
public static string Do_Something()
{
IntPtr tempPointer = DoSomething();
string tempSomething = Marshal.PtrToStringAnsi(tempPointer);
return tempSomething ;
}
The problem had to do with a corrupted heap. The handling of corrupted heaps is different in newer version of Windows and because of that my application crashed. It can be solved through changing the C#-Code or the C++-Code.
Detailed information about the problem can be found here:
http://blogs.msdn.com/b/asiatech/archive/2009/12/24/net-application-may-crash-on-windows-2008-when-calling-function-from-native-c-dll.aspx
I created a DLL in Qt with one function called test. I created another Qt project in which I am able to use the DLL with no problems. I now want to use this DLL in a C# app, however, I am having problems calling the function. I have placed the DLL in the same folder as my C# exe. I import the function like so
[DllImport("TestDll.dll", CharSet = CharSet.Ansi, SetLastError = true)]
private static extern bool test();
I receive the following exception:
EntryPointNotFoundException
I tried adding EntryPoint = test to my DllImport but still receive the same exception
What am I doing wrong?
Have you tried changing option in CharSet? I have been in similar situation. But at that time, I was using a third party Dll compiled in Fortran. Say may be try from Ansi to Unicode.
HTH
I have been attempting to update to the latest HDF5DotNet wrappers (1.8.7) and am getting the following warnings (when running in DEBUG mode from VS2010):
PInvokeStackImbalance was detected
Message: A call to PInvoke function 'HDF5DotNet!::H5Fopen' has unbalanced the stack.
This is likely because the managed PInvoke signature does not match the unmanaged target signature.
Check that the calling convention and parameters of the PInvoke signature match the target unmanaged signature.
I am using the pre-compiled binaries (HDF5DotNet assembly for .NET Framework 4.0 32-bit), but got the same result when I compiled from source.
Strangely, when executing my application that calls the HDF5DotNet wrappers in non-DEBUG mode, I see no problems. I did notice that between 1.8.6 and 1.8.7 all the calling conventions were switched from Cdecl to StdCall. Could this be causing this? I've seen other forums saying the CallingConvention should BE Cdecl...
Thanks!
Yes, calling a stdcall function as cdecl or the other way round causes a stack imbalance. The main difference between these conventions is that with cdecl the caller is responsible for removing the arguments from the stack, with stdcall the callee is responsible.
I guess in release mode you have the same bug. But you don't get the error because some runtime checks are disabled. A native program would crash in most cases where you use the wrong calling convention, but it seems like the .net interop code has a more robust stack handling that masks this problem.