usefor-usefor-03 April 2005

2.2  Headers

   All headers in a news article are compliant with [RFC2822], however
   this specification is less permissive in what can be generated and
   accepted by news agents.  The syntax allowed for news articles is a
   strict subset of the "Internet Message Format", making all messages
   compliant with this specification inherently compliant with
   [RFC2822].  Note however that the converse is not guaranteed to be
   true in all cases.

   General rules which apply to all headers (even those documented in
   [RFC2822] and [RFC2045]) are listed below and those that apply to
   specific headers are described in the relevent sections of this
   document.

   o  All agents MUST generate headers so that at least one space
      immediately follows the ':' separating the header name and the
      header contents (for compatibility with deployed software).  News
      agents MAY accept headers which do not contain the required space.

   o  The header contents of every header line (including the first and
      any that are subsequently folded) MUST contain at least one non-
      whitespace character.

         NOTE: This means that no header content defined by or
         referenced by this document can be empty.  As a result, this
         document updates the <unstructured> construct from Section
         3.2.6 of [RFC2822] as follows:

   unstructured    =  1*( [FWS] utext ) [FWS]

   o  Compliant software MUST NOT generate (but MAY accept) headers of
      more than 998 octets.  This is the only limit on the length of a
      header line prescribed by this standard.  However, specific rules
      to the contrary may apply in particular cases (for example,
      according to [RFC2047] header lines containing encoded-words are
      limited to 76 octets).  [USEAGE] includes suggested limits for
      convenience of display by user agents.

         NOTE: There is NO restriction on the number of lines into which
         a header may be split, and hence there is NO restriction on the
         total length of a header (in particular it may, by suitable
         folding, be made to exceed the 998 octets restriction
         pertaining to a single header line).

   o  The character set for headers is US-ASCII.  Where the use of non-
      ASCII characters is required, they MUST be encoded using the MIME
      mechanisms defined in [RFC2047] and [RFC2231].

--- ../usefor-usefor-02/Headers.out          November 2004
+++ ../usefor-usefor-03/Headers.out          April 2005
@@ -17,9 +17,11 @@
       immediately follows the ':' separating the header name and the
       header contents (for compatibility with deployed software).  News
       agents MAY accept headers which do not contain the required space.
+
    o  The header contents of every header line (including the first and
-      any that are subsequently folded) MUST contain at least one
-      non-whitespace character.
+      any that are subsequently folded) MUST contain at least one non-
+      whitespace character.
+
          NOTE: This means that no header content defined by or
          referenced by this document can be empty.  As a result, this
          document updates the <unstructured> construct from Section
@@ -34,12 +36,14 @@
       according to [RFC2047] header lines containing encoded-words are
       limited to 76 octets).  [USEAGE] includes suggested limits for
       convenience of display by user agents.
+
          NOTE: There is NO restriction on the number of lines into which
          a header may be split, and hence there is NO restriction on the
          total length of a header (in particular it may, by suitable
          folding, be made to exceed the 998 octets restriction
          pertaining to a single header line).
-   o  The character set for headers is US-ASCII.  Where the use of
-      non-ASCII characters is required, they MUST be encoded using the
-      MIME mechanisms defined in [RFC2045] and [RFC2231].
+
+   o  The character set for headers is US-ASCII.  Where the use of non-
+      ASCII characters is required, they MUST be encoded using the MIME
+      mechanisms defined in [RFC2047] and [RFC2231].