// MyClassLib.h
#pragma once
#include "MyLegacyStruct.h"
using namespace System;

namespace MyClassLib {

    public ref class Class1
    {
    protected:
        MyLegacyStruct* m_internalBuffer;

    public:
        Class1() { }
        ~Class1() { }

        MyLegacyStruct* GetBuffer()
        {
            return m_internalBuffer;
        }
    };
}

// MyLegacyStruct.h
#pragma once

namespace MyClassLib {

    typedef struct MyLegacyStruct
    {
        unsigned int m_someVar;

    } MyLegacyStruct;

}

// ConsoleApp.cpp : main project file.

#include "stdafx.h"
#include "MyLegacyStruct.h"

using namespace System;
using namespace MyClassLib;

int main(array<System::String ^> ^args)
{
    Console::WriteLine(L"Hello World");

    Class1^ c1 = gcnew Class1();
    MyLegacyStruct* s1 = c1->GetBuffer(); // <-- This is a problem

    return 0;
}

2>.ConsoleApp.cpp(14) : error C3767: 'MyClassLib::Class1::GetBuffer': candidate function(s) not accessible