System.EntryPointNotFoundException when importing functions from a dll

Question

I have a Dll that was created with VC++. I'm very sure the Dll works, because when I import it into a test program written in VC++, it works and gives the correct data.

But when I try to use it in a VB.Net test program, it throws a System.EntryPointNotFoundException

All of the Dll functions uses stdcall.

Here's the source code of the VB.NET test program:

Public Class Form1
    Public Declare Function func Lib "dll.dll" () As Integer

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Label1.Text = func().ToString()
    End Sub
End Class

Here is the source code of the DLL

#include <SDKDDKVer.h>
#define WIN32_LEAN_AND_MEAN
#include <Windows.h>
__declspec(dllexport)int _stdcall func();

BOOL APIENTRY DllMain(HMODULE hModule,DWORD l_reason_for_call, LPVOID lpReserved)
{
    return TRUE;
}
int _stdcall func()
{
    return 123;
}

Can anyone help?

Answer 1

Never mind, I figured it out. I needed to add a Alias to my declarations.

I ran dumpbin on my dll and found the import names.

So my declaration name should have been should have been:

Public Declare Function func Lib "dll.dll" Alias "?func@@YG_NXZ" As Integer