On Thu, 6 May 1999, Hans-Georg v. Zezschwitz wrote:
> > Not at present. There probably ought to be an expansion operator called
> > "escape" which converts a string into all printing characters. As there
> > is already a function in Exim to do this job, adding the operator should
> > be easy. I will look into it.
>
> I don't get the point yet.
(1) I think it might be a generally useful function to have, not only
for use when generating headers, but in other cases when you want to be
sure you have only printing characters.
> What is this function doing?
(2) Turning non-printing characters into escape sequences such as \n for
newline, etc. With print_topbitchars set, this will apply only to codes
less than 32.
> If you'd like to convert those ugly things like german umlauts in the
> headers to something meeting the definitions of RFC 822, you should
> use the methods of RFC 2047. However, this requires knowledge about
> the charset in which the sender sent his 8-bit-characters. While
> this is mostly ISO-8859-1 in the western european area, it would
> still be just some kind of assumption the MTA is making.
Oh, quite. I don't want to get fancy like that. As I said, I think the
whole 7-bit thing is a fantasy. However, problems with characters less
than 32 can be real.
--
Philip Hazel University of Cambridge Computing Service,
ph10@??? Cambridge, England. Phone: +44 1223 334714.
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