I have a couple macros that run on PC and Macs. I learned that I have
to put a "#" in front of the file access code to make the macro utilize
the appropriate OS commands:

Example:

#If Win32 Then
LoadFileName = Application.GetOpenFilename(FileFilter)
#ElseIf Mac Then
LoadFileName = Application.GetOpenFilename()
#End If

Can someone explain why the # is necessary and what it means?

Thanks