在C＃中导入Visual C ++ DLL时的非托管签名

Question

I have a DLL that was developed in Visual C++, and I've started importing it's functionality to ac# project using DllImport . I've already implemented a few methods and they work well.

For that specific method I'm getting the following error:

Additional information: A call to PInvoke function 'SdkTest!SdkTest.Program::CLIENT_RealPlay' 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.

The c++ method I'm trying to implement has this signature:

CLIENT_NET_API LLONG CALL_METHOD CLIENT_RealPlay(LLONG lLoginID, int nChannelID, HWND hWnd);

With the following definitions:

#define CLIENT_NET_API  __declspec(dllimport)
#define CALL_METHOD     __stdcall
#define LLONG   LONG

My c# impelmentation is the following:

[DllImport("dhnetsdk.dll")]
public static extern long CLIENT_RealPlay(long lLoginID, int nChannelID, IntPtr hWnd);

(I've read that HWND equivalent in c# is IntPtr , but I've also tried to put int, long, object...)

I also tried doing DllImport in the following way (As suggested in some posts and worked for some other methods I'm using):

[DllImport("dhnetsdk.dll", CharSet = CharSet.Ansi, CallingConvention = CallingConvention.Cdecl)]

No matter what I try I'm getting the same error. What am I miss understanding? If an internal exception in the c++ code is thrown, what kind of exception will I get in my code?

Answer 1

#define LLONG   LONG

Now, LONG maps to long , which is a signed 32 bit type on Windows. Therefore, using long in your C# code is wrong because C# long is a 64 bit type. You need to use int instead. Like this:

[DllImport("dhnetsdk.dll")]
public static extern int CLIENT_RealPlay(int lLoginID, int nChannelID, IntPtr hWnd);

Answer 2

The c++ function is declared with calling convention stdcall, but you are calling it with cdecl.

In my experience, call stack corruptions are mostly caused by using the wrong calling convention.