How to call a labview dll from visual c++ 2005/2008

[Little_Helper]

Hi

I am looking into making some DLL files in LabVIEW 8.5 that can be called from other programming environments. Initially I want to call a simple DLL that multiplies two numbers and gives the result. I have made the VI / DLL with the corresponding in- and outputs and compiled it. So now I have got my DLL, SharedLib.h, SharedLib.lib etc.

Can anyone now show me how I can call this DLL from e.g. Visual C++ 2005/2008?

Best regards

Simon

[smercurio_fc]

Will this be using .NET? If so, you may want to take a look at this article: How Do I Use a LabVIEW DLL in Microsoft Visual Studio.NET?

[Little_Helper]

Hi Smercurio

Yea it's something like that I am looking for, especially the example from MSDN with a C++ example.

To be honest, I don't normally program in C++, I just have to do some pretest on some DLLs before I send it on to some other people:-)

So, the C++ example I found to be the closest one to what I need, is

using namespace System::Runtime::InteropServices;

typedef void* HWND;
[DllImport("user32", CharSet=CharSet::Auto)]
extern "C" IntPtr MessageBox(HWND hWnd,
                          String* pText,
                          String* pCaption,
                          unsigned int uType);
void main(void) {
     String* pText = L"Hello World!";
     String* pCaption = L"Platform Invoke Sample";
     MessageBox(0, pText, pCaption, 0);
}

 To call my DLL, I have got the following parameters

       double mycalculator(double myinput1, double myinput2)

which returns a result.

To test this I have installed Microsoft Visual C++ 2008 Express Edition.

Now I just need some clever people to help me with a little test example 🙂

Best regards

Simon

[snowpunter]

Here's an older tutorial but it still applies for newer versions of LV and Visual Studio. Should do the trick.

-snow

[smercurio_fc]

That tutorial does not apply to .NET. .NET calls DLLs as unmanaged code. Visual C++ 6 had no concept of managed/unmanaged calls.

[snowpunter]

Are you using Managed C++? You didn't specify that in your original post. If you're using Unmanaged C++ then the tutorial is still relevant.

Anyway, if you're using Managed you use PInvoke instead of natively calling the dll.

-snow