Xref: utzoo comp.lang.c:35785 comp.std.c:4237
Newsgroups: comp.lang.c,comp.std.c
Path: utzoo!utgpu!watserv1!watmath!datangua
From: datangua@watmath.waterloo.edu (David Tanguay)
Subject: Re: Dereferencing Typecast Integer Literals
Organization: University of Waterloo
Date: Mon, 4 Feb 91 23:41:42 GMT
Message-ID: <1991Feb4.234142.26867@watmath.waterloo.edu>
Followup-To: comp.std.c
References: <15067@smoke.brl.mil>
Lines: 15

In article <15067@smoke.brl.mil> gwyn@smoke.brl.mil (Doug Gwyn) writes:
>Also, each implementation is required to
>provide SOME integral type to which any data pointer can be cast such
>that upon subsequent cast back to the same type of pointer, the new
>pointer value will compare equal to the old value.

Where does the standard say this?  3.3.4 says a pointer may be converted
to some integral type, and that an integer may be converted to a pointer,
but the result is implementation defined. Whether or not the pointer
value is preserved across pointer -> int -> pointer is implementation
defined. For example, the pointer -> integer conversion could drop the
segment of the pointer, and the integer -> pointer could apply some
default segment (the integer gets the offset).
-- 
David Tanguay            Software Development Group, University of Waterloo