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From: gwyn@smoke.brl.mil (Doug Gwyn)
Newsgroups: comp.lang.c
Subject: Re: type and size of bit-fields
Message-ID: <15540@smoke.brl.mil>
Date: 21 Mar 91 04:40:02 GMT
References: <12638@adobe.UUCP> <1991Mar20.172906.3645@zoo.toronto.edu> <1991Mar20.224317.1265@grebyn.com>
Organization: U.S. Army Ballistic Research Laboratory, APG, MD.
Lines: 14

In article <1991Mar20.224317.1265@grebyn.com> ckp@grebyn.com (Checkpoint Technologies) writes:
>...  This would seem to prohibit writing records with bit fields to
>external storage, if there's any chance that the program in question
>will ever be recompiled and then asked to deal with the same records.

Yes, indeed, if any program other than THE SAME PROCESS THAT WROTE IT
reads a binary "dump" of C data structures, there is no guarantee that
it will have the appropriate format.

>Perhaps the Standard has something to say in this regard?

It does NOT require all implementations to make the same choice for
bit field ordering, structure member padding, etc.  Successive
releases of the "same" compiler are considered different implementations.