On Fri, 6 Jul 2007, Toralf Lund wrote:
> What do I get if I do something like
>
> ${eval:$some_variable+1}
>
> when "some_variable" is not actually defined?
It depends on the variable. In the case of $acl_ variables it also
depends on whether you have set strict_acl_vars or not. Many variables
are just empty strings when nothing in particular has been put into them
- for example $sender_host_address in a non-TCP/IP-submitted message.
However, other variables contains something. A quick look at the manual
shows, for example, that $authentication_failed is either "0" or "1".
--
Philip Hazel University of Cambridge Computing Service
Get the Exim 4 book: http://www.uit.co.uk/exim-book
