Imports System.IO
Imports System.Threading
Imports System.Threading.Tasks

Friend Module Optimise

Friend Results() As Single

    Sub Go()
    Parallel.Invoke(New Action(AddressOf Optimise), New Action(AddressOf ExportResults))
End Sub

Sub Optimise()

   redim results(1000)

   For i = 1 To 1000
            'results(i) = do some calcs
            'do I need to lock results() somehow? Or as ExportResults() is the only other thing accessing am I OK to leave unlocked?
   Next

End Sub

Sub ExportResults()

    'how can this thread monitor results()?
    '(is results locked?)
    'How can it access results without interupting optimise() thread?

End Sub

End Module