Managed C# String to Unmanged C++DLL

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I swear, I've tried everything I've found online, and I'm still getting a PINVOKE error.
"A call to PInvoke function 'BioPacVideo!BioPacVideo.VideoWrapper::SetFName' 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."

on the C# side

[DllImport(@".\VideoWrapper.dll")]
        public static extern void SetFName(StringBuilder FName, int FStart);
        //public static extern void SetFName([MarshalAs(UnmanagedType.LPStr)]string FName, int FStart);

on the C++ side

extern "C" _declspec(dllexport) void SetFName(LPTSTR FName, int FileStart);

Posted 2-Mar-11 10:34am

DarkKobold

Updated 2-Mar-11 10:55am

Yusuf

v2

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Sergey Alexandrovich Kryukov · Accepted Answer · 2011-03-02T11:51:00

Solution 1

I immediately can see a mistake: you use LPStr which will marshal 1-byte null-terminated string, but you need platform-dependent string (LPTSTR).

Try this:

C#

[DllImport(@".\VideoWrapper.dll")]
public static extern void SetFName(
    [MarshalAs(UnmanagedType.LPTStr)]string FName,
    int FStart);

—SA

Posted 2-Mar-11 11:51am

Sergey Alexandrovich Kryukov

Updated 2-Mar-11 11:55am

v3