pinvokestackimbalance -- how can I fix this or turn it off?

Question

I just switched to vs2010 from vs2008. Exact same solution, except now every single call to a C++ dll yields a 'pinvokestackimbalance' exception.

This exception does not get fired in 2008. I have complete access to the C++ dll and to the calling application. There does not appear to be any problem with the pinvoke, but this problem is making debugging other problems impossible; the IDE is stopping constantly to tell me about these things.

For instance, here's the C# signature:

    [DllImport("ImageOperations.dll")]
    static extern void FasterFunction(
        [MarshalAs(UnmanagedType.LPArray)]ushort[] inImage, //IntPtr inImage, 
        [MarshalAs(UnmanagedType.LPArray)]byte[] outImage, //IntPtr outImage, 
        int inTotalSize, int inWindow, int inLevel);

Here's what it looks like on the C++ side:

#ifdef OPERATIONS_EXPORTS
#define OPERATIONS_API __declspec(dllexport)
#else
#define OPERATIONS_API __declspec(dllimport)
#endif
extern "C" {


OPERATIONS_API void __cdecl FasterFunction(unsigned short* inArray, 
                                       unsigned char* outRemappedImage,
                                       int inTotalSize, 
                                       int inWindow, int inLevel);

}

What's different between vs2010 and vs2008 that would cause these exceptions to get thrown? Should I be adding a different set of parameters to the DllImport directive?

Coucal

Answer 1

First, understand that the code is wrong (and always has been). The "pInvokeStackImbalance" is not an exception per se, but a managed debugging assistant. It was off by default in VS2008, but a lot of people did not turn it on, so it's on by default in VS2010. The MDA does not run in Release mode, so it won't trigger if you build for release.

In your case, the calling convention is incorrect. DllImport defaults to CallingConvention.WinApi, which is identical to CallingConvention.StdCall for x86 desktop code. It should be CallingConvention.Cdecl.

This can be done by editing the line [DllImport("ImageOperations.dll")] to be:

[DllImport("ImageOperations.dll", CallingConvention = CallingConvention.Cdecl)]

For more information, see this MSDN reference

Ulane

Thanks! The exceptions have definitely stopped firing. Maybe this will solve some of the long-term stability problems we were having as well. – Coucal

Quite possibly. This particular type of stack imbalance is actually somewhat common; it doesn't cause any errors right away but will slowly consume the thread's stack. Eventually, "bad things" will happen. The CLR is usually able to raise a StackOverflowException, but using, catch, and finally blocks really complicate things when the stack is full. For this reason, starting in .NET 2.0, a StackOverflowException will just terminate the process. – Ulane

More information on interop calling conventions here. – Extremism

Excellent, this pointed me in the right direction after trying to update some projects to .Net 4.0. After changing the calling convention in the C# source to Cdecl, I then had to make a change to our *.h and *.c files to use '__cdecl`. – Chiapas

Thank you! This response saved the day. In my case, the issue arose from referencing a Visual C++ 8.0 (Visual Studio 2008) DLL in a Visual Studio 2010 project. – Dolerite

Thanks (+1). Same issue for me. Had no explicit calling convention set but declaration was __cdecl. – Mcglothlin

Answer 2

To turn it off:

1. CTRL + ALT + E
2. Under "Managed Debugging Assistants" uncheck PInvokeStackImbalance.

Swore

Never, never, never shoot the messenger. A stack imbalance will eat your liver, with fava beans, sooner or later. – Loess

Answer 3

Better to solve this issue its not much difficult here I am mentioning some of the methods, it may same as some of my friends mentioned above. I am working with PCSC a Smartcard application I spend around one week, get pissed off did lot of changes finally got the solutions.

For me its work with PInvoke Extension which I installed for VS2010 you can download it here http://www.red-gate.com/products/dotnet-development/pinvoke/

Download it and install it, Close visual studio and open again you can find extension at Menu Bar.

If the error is because of signature not matching you just click on PInvoke.net> Insert PInvoke Signatures

The new window will appear like below

Enter the name of the dll and click on search you can see the all the functions of that dll in search result window, Click on the function you will get a signature for that particular Function.

Use that signature and you need to modify your programs according to that Signature, Mostly the data Type.

This solve my problem you might have different problem like callingConvention or additional attributes need to specify while importing dll.

Happy Coding Be well!

Emission

Most DLLs can't be found in the search window. Unfortunate as it looks pretty neat. – Caveat

Answer 4

I got this problem also when using VS2010. What it is: Visual Studio defaults to 64 bit code for 'any CPU'. The pointers to variables (eg. strings) now become 64 bit when calling your external Dlls, where as all your reliable and trusted Dlls use 32 bit pointers.

Don't assume there is anything wrong with your Dlls, there isn't.

Change your VS settings to generate X86 code like this (Express versions of C#)

1. go to Tools -> Options.
2. In the bottom-left corner of the Options dialog, check the box that says, "Show all settings".
3. In the tree-view on the left hand side, select "Projects and Solutions".
4. In the options on the right, check the box that says, "Show advanced build configuraions."
5. Click OK.
6. Go to Build -> Configuration Manager...
7. In the Platform column next to your project, click the combobox and select "".
8. In the "New platform" setting, choose "x86".
9. Click OK.
10. Click Close.

I notice also, that even though computers have doubled in power every 12 months, my current computer with 1gig of RAM, seems no faster than my first 486 with 4 Meg. Don't worry about using 64 bit code, it's not going to be faster or better because it is built on a huge cumbersome object-orientated tower of bloat.

Comforter

Thanks for the tips, I'll check them out. But if you're running a Windows 64 bit OS with only 1 gb of RAM, you're going to have speed issues. You should upgrade to at least 4 gb, otherwise you'll have swapping issues. 64 bit OS's afford having more information in memory rather than on disk, and that change can produce great speed increases, depending on the operation. If your machine isn't faster than a 486, might be time to do some virus checking :) – Coucal

This worked, thank you so much! saved me hours if not days! – Dominoes

Answer 5

I tried to call dll with the CallingConvention is ThisCall and it worked for me. Here is my code working with BLOB MS Sql Server.

[DllImport("sqlncli11.dll", SetLastError = true, CharSet = CharSet.Unicode, CallingConvention = CallingConvention.ThisCall)]
            private static extern SafeFileHandle OpenSqlFilestream(
                        string FilestreamPath,
                        UInt32 DesiredAccess,
                        UInt32 OpenOptions,
                        byte[] FilestreamTransactionContext,
                        UInt32 FilestreamTransactionContextLength,
                        Int64 AllocationSize);

More at: https://msdn.microsoft.com/en-us/library/system.runtime.interopservices.callingconvention(v=vs.110).aspx

Tsarevitch