From: Pete Resnick <presnick(_at_)qualcomm(_dot_)com>
Subject: Re: limitation of the number of To: (and Cc:)
You say there are "many messages" with multiple To: and Cc: fields.
What clients are producing these?
I can enumerate three types:
(1) Consider a UA which allows a user to set Cc: field optionally. A
user may always uses the option for backup. That is, all message
which he sends will come back to him thanks to Cc:.
Such a UA generates another Cc: field (and To: field) when
replying. Note the Cc: field above is optional.
Not necessarily; the agent is free to combine all the To: addresses
into a single To: field and all the Cc: addresses into a single Cc: field.
The user agents I am familiar with do this.
Or perhaps you're confusing the idea of a multiple fields with multiple
addresses? Multiple addresses in a single field are fine, multiple fields are
not.
(2) Consider a UA which allows a user to edit the header of a draft
message. (UAs on Emacs, for example.) With such a UA, a user may
write multiple To:/Cc: fields.
Again, the multiple addresses can be combined onto single fields. And again the
user agents I'm familiar with do this.
(3) Some shell scripts generate a message which contains multiple To:,
one address by one To: field.
I can see how a naive shell script might do this; the solution is not
to use such naive scripts.
Ned