Beginner Visual C++ Issue: cannot convert parameter 1 from 'void (__cdecl *)(void *)' to 'void (__cdecl *)(void *)'

Question

So I'm a predominantly Linux programmer who's recently got a job working with Windows. I've developed some numerical code, but now need to put a simple GUI on.

At the moment I have a button with an onClick event with calls a function called start which kicks off the numerical stuff. But this freezes the GUI so I want to put the call to start into a worker thread.

I've declared start like this: void __cdecl start(void* args). I added the __cdec1 as I was previously getting the error: error C2664: '_beginthread' : cannot convert parameter 1 from 'void (__clrcall *)(void *)' to 'void (__cdecl *)(void *)'.

Now when the button is clicked the following code runs:

output->Text = "Starting";
_beginthread(start, 0, NULL);
output->Text = "Done";

This gives me the confusing error cannot convert parameter 1 from 'void (__cdecl *)(void *)' to 'void (__cdecl *)(void *)'.

If anyone can see where I'm going wrong I'd be eternally grateful.