Question: When I use `man fcntl' got the message:

```
No manual entry for fcntl

```

which the pkg is needed to install?

ps. I use debian.

Answer: 
The NULL answer from [IS\_MEMBER](http://msdn.microsoft.com/en-us/library/ms186271(SQL.90).aspx) means that SQL Server does not recognise the Windows group.

It looks at the login token from your connection. It does not query Active Directory.

From the BOL link:

> 
> IS\_MEMBER determines Windows group
>  membership by examining an access
>  token that is created by Windows. The
>  access token does not reflect changes
>  in group membership that are made
>  after a user connects to an instance
>  of SQL Server.
> 
> 
> 

So, even though doamin\kieran is in the group you'll probably need to log out and back in so your login token is updated with the group membership.

It should all work in your UDF (unless you have EXECUTE AS USER or OWNER in the UDF)
Check your `ERRORLOG` and see if there is any error indicating that the SQL Server service cannot connect to the 'domain' Active Directory.