Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!seismo!ll-xn!mit-eddie!genrad!panda!teddy!jpn
From: jpn@teddy.UUCP (John P. Nelson)
Newsgroups: comp.unix.wizards,comp.lang.c
Subject: Re: bitfields
Message-ID: <3523@teddy.UUCP>
Date: Mon, 1-Dec-86 07:57:44 EST
Article-I.D.: teddy.3523
Posted: Mon Dec  1 07:57:44 1986
Date-Received: Mon, 1-Dec-86 19:57:01 EST
References: <844@sphinx.UChicago.UUCP>
Reply-To: jpn@teddy.UUCP (John P. Nelson)
Followup-To: comp.lang.c
Distribution: na
Organization: GenRad, Inc., Concord, Mass.
Lines: 21
Xref: mnetor comp.unix.wizards:208 comp.lang.c:191

>Ok, folks, here is the burining question of the hour:  how are bit fields in
>C dealt with?  As I read K&R arrays of bit fields are allowed, HOWEVER, in
>the Microsoft C compiler Version 4.0, they explicitly state that they are not
>allowed.

If K&R is Kernighan and Ritchie, I suggest you reread it.  Arrays of bitfields
are EXPLICITLY disallowed  (See the last paragraph in section 6.7) - but in
any case, an array of bitfields is impossible, not just difficult - Remember
that a reference to an array (not just an element of it) evaluates to an
ADDRESS - However, taking the address of a bit field is also explicitly
disallowed.  Here is part of the relavent paragraph from K&R

     Other restritrictions (of bit fields) to bear in mind:  ...   They are
     not arrays; they do not have addresses, so the & operator cannot be
     applied to them.

and again, in appendix A where structures are formally defined (section 8.5):

     ... In all implementations, there are no arrays of fields, and the
     address-of operator '&' may not be applied to them, so that there are no
     pointers to fields.