Re: [exim] Idea: Predefined macros

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Autor: Philip Hazel
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A: W B Hacker
CC: exim-users
Assumpte: Re: [exim] Idea: Predefined macros
On Wed, 2 May 2007, W B Hacker wrote:

> But one might then ask, how MACRO's compare in potential load with:
>
> - hostlists
>
> - lookups (in general)
>
> - lookups involving SQL calls


Indeed. But all of those items can be omitted from the config if you
don't want them. Predefined macros would not be optional.

> Correct me if I am wrong, but I am under the impressions that a 'hostlist' is
> handled much as the described parsing for a MACRO, i.e. - end-to-end expansion &
> substitution, called on or not...


No. A hostlist is expanded only when Exim is about to scan it. That is,
only when it is about to be used.

> - while a 'lookup' - be it file, db, or SQL - is ignored until actually
> encountered in acl that *uses* it, IOW, skipped in many cases.


Indeed.

-- 
Philip Hazel            University of Cambridge Computing Service
Get the Exim 4 book:    http://www.uit.co.uk/exim-book