Path: utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!microsoft!jimad
From: jimad@microsoft.UUCP (Jim ADCOCK)
Newsgroups: comp.lang.c++
Subject: Re: Comparison functions for qsort() and bsearch()
Keywords: Sun, C++
Message-ID: <70023@microsoft.UUCP>
Date: 15 Jan 91 00:23:13 GMT
References: <1990Dec26.160636.15566@clear.com> <1991Jan2.191630.18581@Think.COM> <60328@microsoft.UUCP> <278A3278.1241@tct.uucp>
Reply-To: jimad@microsoft.UUCP (Jim ADCOCK)
Organization: Microsoft Corp., Redmond WA
Lines: 33

In article <278A3278.1241@tct.uucp> chip@tct.uucp (Chip Salzenberg) writes:
|According to jimad@microsoft.UUCP (Jim ADCOCK):
|>I claim either:
|>
|>1) Casts from a void* to a pointer to an object of some class already 
|>defined are in error.
|>or
|>2) The definitions given by ARM pgs 67-71 are in error.
|
|From the ARM, page 36 [commentary]:
|"ANSI C allows an IMPLICIT conversion from a pointer to |void| to a
|pointer to another object type (but not to a pointer to function type
|...); in C++ a |void*| cannot be assigned to an object of any type
|other than |void*| WITHOUT AN EXPLICIT CAST."  (Emphasis mine.)
|
|So if you _do_ use an explicit cast, you may convert a |void*| to an
|object of some class already defined.

I disagree.  1) the text you quote is in the form of a prohibition.  
A prohibition cannot create permissions that do not otherwise 
exist.  2) the text you quote is a commentary, and thus not binding
anyway.

The commentary implies that one _might_ have some rights in some cases
to cast from void using explicit cast -- but does not imply where and
when and with what restrictions those rights might exist.

|If the text of the ARM does not explicitly support this point, then it
|would seem there is an oversight in the text.

Agreed that this is the most probable conclusion -- but, this conclusion
doesn't clarify what the oversight was, nor how the ansification 
[isofication?] committee will fix it.