Made a function in C but how to...?

Question

he examples given by Sir....if I change a little bit then the program runs OK.

But I don't know how to store the result in C#. Please assist.......

So I mention the code here:-

VC++ Code:-

In Ctest1.h

#include<stdio.h>

#include "pch.h"

#pragma once

class __declspec(dllexport) Ctest1

{

public:

Ctest1();

~Ctest1();

char* func();

};

In Ctest1.cpp

#include "pch.h"

#include "Ctest1.h"

char* Ctest1::func()

{

char sname[] = { "kkk" };

return sname;

}

Ctest1::Ctest1()

{}

Ctest1::~Ctest1()

{}

In Caller.h

#include "Ctest1.h"

#include "pch.h"

#ifdef __cplusplus

extern "C"

{

#endif

extern __declspec(dllexport) Ctest1* _Create();

extern __declspec(dllexport)void dispose(Ctest1* _pObject);

extern __declspec(dllexport)char* func(Ctest1* _pObject);

#ifdef __cplusplus

}

#endif

In Caller.cpp:-

#include "pch.h"

#include "Caller.h"

Ctest1* _Create()

{

//Ctest1 c = new Ctest1();

return new Ctest1();

}

void dispose(Ctest1* _pObject)

{

if (_pObject != NULL)

{

delete _pObject;

_pObject = NULL;

}

}

char* func(Ctest1* _pObject)

{

if (_pObject != NULL)

{

char* str = _pObject->func();

return str;

}

}

And in C# Code:-

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Runtime.InteropServices;

using System.Text;

using System.Threading.Tasks;

using System.Windows.Forms;

namespace WindowsFormsApp1

{

public partial class Form1 : Form

{

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

public static extern IntPtr _Create();

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

public static extern void dispose(IntPtr pCtest1);

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

public static extern IntPtr func(IntPtr pTest);

public Form1()

{

InitializeComponent();

}

private void button1_Click(object sender, EventArgs e)

{

IntPtr ptestClass = _Create();

IntPtr p= func(ptestClass);

/// Now how to get the string in C-funcion

dispose(ptestClass);

}

}

}

So sir how to get the string returned from C++ and store it in C#