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From: jbs@eddie.MIT.EDU (Jeff Siegal)
Newsgroups: comp.lang.c,news.software.b
Subject: Re: passing NULL to functions
Message-ID: <5619@eddie.MIT.EDU>
Date: Mon, 27-Apr-87 17:14:58 EDT
Article-I.D.: eddie.5619
Posted: Mon Apr 27 17:14:58 1987
Date-Received: Wed, 29-Apr-87 02:14:08 EDT
References: <150@sds.UUCP> <1129@ius2.cs.cmu.edu>
Reply-To: jbs@eddie.MIT.EDU (Jeff Siegal)
Organization: MIT, EE/CS Computer Facilities, Cambridge, MA
Lines: 14
Xref: mnetor comp.lang.c:1924 news.software.b:556

In article <1129@ius2.cs.cmu.edu> edw@ius2.cs.cmu.edu (Eddie Wyatt) writes:
>  Are you saying that you are not guarenteed sizeof(char *) == sizeof(int *)
>sizeof(long *) == sizeof(whatever *)?  I'm amazed at this because I have
>never run across this problem but then again I haven't worked on that many
>different architectures.  Not that I doubt you, but could you show me
>where you benifit or need pointers of different size?

On word-addressed machines (like the PDP-10), a pointer to a smaller
object (smaller than a word, that is) must include not only the
address of the word containing the object, but also the offset within
the word.  This also applies to byte-addressed machines which support
bitfields (except that pointers to bitfields do not exist in C). 

Jeff Siegal