Exploring use of Dir("\testdir\nul")

[MLH]

Back in '98, Trevor Best posted a 1-liner I
consider to be an excellent suggestion:

Dir("\testdir\nul")

If I have an actual directort named c:\bat
and I run Dir("c:\bat\nul") in the immediate
window, 'nul' is returned. On the other hand,
if I run Dir("c:\baat\nul"), the debug window
just displays an empty line. I was wondering
if that empty line was equivalent to Null and
if I could use IsNull(Dir("c:\baat\nul")) inside
a class module to determine existence of a
directory?

[Wayne Morgan]

Dir() returns a zero length string (""), not Null if it doesn't find the
file. So, instead of IsNull(Dir(etc.)), you would use

If Dir("C:\Baat\Nul") = "" Then

--
Wayne Morgan
MS Access MVP
"MLH" <CR**@NorthState.net> wrote in message
news:ht********************************@4ax.com...

Back in '98, Trevor Best posted a 1-liner I
consider to be an excellent suggestion:

Dir("\testdir\nul")

If I have an actual directort named c:\bat
and I run Dir("c:\bat\nul") in the immediate
window, 'nul' is returned. On the other hand,
if I run Dir("c:\baat\nul"), the debug window
just displays an empty line. I was wondering
if that empty line was equivalent to Null and
if I could use IsNull(Dir("c:\baat\nul")) inside
a class module to determine existence of a
directory?

[MLH]

On Thu, 15 Sep 2005 18:23:32 GMT, "Wayne Morgan"
<co***************************@hotmail.com> wrote:

Dir() returns a zero length string (""), not Null if it doesn't find the
file. So, instead of IsNull(Dir(etc.)), you would use

If Dir("C:\Baat\Nul") = "" Then

Good point. Thx.
So, Dir("C:\Baat\Nul") returns one of two strings: "Nul" or "".
Sound about right? At any rate, if it returns anything other
than the string "nul", then the directory does not exist.

[Trevor Best]

MLH wrote:

On Thu, 15 Sep 2005 18:23:32 GMT, "Wayne Morgan"
<co***************************@hotmail.com> wrote:

Dir() returns a zero length string (""), not Null if it doesn't find the
file. So, instead of IsNull(Dir(etc.)), you would use

If Dir("C:\Baat\Nul") = "" Then

Good point. Thx.
So, Dir("C:\Baat\Nul") returns one of two strings: "Nul" or "".
Sound about right? At any rate, if it returns anything other
than the string "nul", then the directory does not exist.

Yes, it will be one of the two values.

I would point out that this method hasn't always worked in the past, on
Novell servers accessing from MS-DOS it didn't work, on a directory that
didn't exist the Novell driver would pass the request back to DOS, DOS
shrugged it's shoulders and said "yeah OK, it must exist then" :-\

Never seen this behavior on local disks or Windows servers though.