RFC 2822 Sections 2.2.1 and 2.2.3 clearly say that all unstructure
headers, including Subject headers, can be folded and unfolded, and how
to do so.
Following those rules, the subject line shown below can legitimately be
unfolded to this, and then refolded in another fashion.
Subject: Discussions concerning foo, bar and baz. Part I. Foo.
That is, a header field that consists of multiple lines is, by
definition, a folded field. Section 2.2.3 says explicitly:
Each header field is logically a single line of characters comprising
the field name, the colon, and the field body.
I don't think it can get clearer than this.
Tony Hansen
tony(_at_)att(_dot_)com
Charles Lindsey wrote:
In Jacob Palme writes:
>I think it is very reasonable to assume that a Subject cannot
>contain any line breaks, and thus that any line breaks in
>Subject are removed, and that there should be not more than
>a single space where the line break occurred.
Why would you assume that? Surely the content of the Subject is up to the
author?
Subject: Discussions concerning foo, bar and baz.
Part I. Foo.
If some "smart" receiving agent reformats that, it might appear as
Subject: Discussions concerning foo, bar and baz. Part
I. Foo.
For sure, the transport system should not change any folding. If the
recipient is foolish enough to buy such an "oversmart" agent, then that is
his misfortune.