You could also call a given function that will do what you want for any specific OS if you don't want to split it up into files:
?Win32
DoThisLinWin()
?Linux
DoThisLinWin()
?MacOS
DoThisMacOnly()
?
Function DoThisMacOnly()
.
.
.
End Function
Function DoThisLinWin()
.
.
.
End Function
?Win32
DoThisLinWin()
?Linux
DoThisLinWin()
?MacOS
DoThisMacOnly()
?
Function DoThisMacOnly()
.
.
.
End Function
Function DoThisLinWin()
.
.
.
End Function