Question

Would it be easy to convert the following function so that instead of just 0 or 1 it gave the following three outputs:

0 – means file closed
1 – means file is already open
2 – means file does not exist

Here’s the Function

Function IsFileReadOnlyOpen(FileName As String)

Dim iFilenum As Long
Dim iErr As Long

On Error Resume Next
iFilenum = FreeFile()
Open FileName For Input Lock Read As #iFilenum
Close iFilenum
iErr = Err
On Error GoTo 0

Select Case iErr
 Case 0:    IsFileReadOnlyOpen = 0
 Case 70:   IsFileReadOnlyOpen = 1
 Case Else: Error iErr
End Select

End Function

Answer 1

You could add this at the beginning of your function:

If Dir(FileName) = "" Then 'File does not exist
    IsFileReadOnlyOpen = 2
    Exit Function 'Or not - I don't know if you want to create the file or exit in that case.
End If

I agree with the comment that you should use enum to make it easier to understand.

PS: As commented by Martin Milan this might cause issues. Alternatively, you can use this:

With New FileSystemObject
    If .FileExists(FileName) Then
        IsFileReadOnlyOpen = 2
        Exit Function 'Or not - I don't know if you want to create the file or exit in that case.
    End If
End With