vérifier qu'un fichier est ouvert

Function IsFileOpen(filename As String)
' (code Microsoft :
' http://support.microsoft.com/default.aspx?scid=kb;EN-US;q138621)
Dim filenum As Integer, errnum As Integer

  On Error Resume Next   ' Turn error checking off.
  filenum = FreeFile()   ' Get a free file number.
  ' Attempt to open the file and lock it.
  Open filename For Input Lock Read As #filenum
  Close filenum          ' Close the file.
  errnum = Err           ' Save the error number that occurred.
  On Error GoTo 0        ' Turn error checking back on.

  ' Check to see which error occurred.
  Select Case errnum
           
    ' No error occurred.
    ' File is NOT already open by another user.
    Case 0
      IsFileOpen = False

    ' Error number for "Permission Denied."
    ' File is already opened by another user.
    Case 70
      IsFileOpen = True

    ' Another error occurred, file is being queried.
    Case Else
      Error errnum
  End Select

End Function