How to open a PDF companion file?

You can open companion files in external applications thanks to the following VBA code snippet. For instance, this will open the PDF file named UserGuide.pdf.

Sub OpenUserGuide()

   FileCopy PathToCompiledFile("UserGuide.pdf"), Environ("temp") & "/UserGuide.pdf")

   ActiveWorkbook.FollowHyperlink Environ("temp") & "/UserGuide.pdf"

End Sub