PInvokeStackImbalance C# call to unmanaged C++ function

Question

After switching to VS2010, the managed debug assistant is displaying an error about an unbalanced stack from a call to an unmanaged C++ function from a C# application.

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Answer 1

It's good.I update function define as follow:

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

It works well.

Answer 2

As mentioned in Dane Rose's comment, you can either use __stdcall on your C++ function or declare CallingConvention = CallingConvention.Cdecl on your DllImport.

Answer 3

You specify no padding in your C# declaration of the struct, but not in the C++ version. Since you are mixing char arrays that are not all multiples of four and an odd number of 2 byte shorts, the compiler is probably inserting padding within the struct and add the end.

Try wrapping the struct in a #pragma pack to ensure no padding.

#pragma pack(push)
#pragma pack(1)

// The struct

#pragma pack(pop)

Answer 4

Had the same problem as described - unmanaged C++ app that has worked perfectly for years. When we upgraded to VS2010, we started getting PInvokeStackUnbalanced messages.

adding "__stdcall" to the C++ signature as described above made the issue go away.

Answer 5

You specify stdcall in C# but not in C++, a mismatch here will lead to both the function and the caller popping arguments off of the stack.

On the other hand there is a compiler switch that will turn on stdcall as the default calling convention, (-Gz) are you using that?

Or try this in your C++

short __stdcall SuperSpecialOpenFileFunc(SuperSpecialStruct * stuff);