🚀 go-pugleaf

According to dhoyt@vx.acs.umn.edu:
>In article <27D5708A.29CF@tct.uucp>, chip@tct.uucp (Chip Salzenberg) writes...
>>[ANSI C requires |void*| and |char*| to be identically represented]
>
>The reason that ANSI made this true (mostly, anyway) is because there
>existed a huge body of code that depended on this equivalence.

This statement is patently false, as proven by the next statement,
which is true:

>K&R didn't have a void type in the first place

It is impossible for K&R programs to depend on |void*|, since they
don't mention |void*|.

Point 1: ANSI created |void*| explicitly for the purpose of holding
any data address whatsoever.  That's why, for example, the first two
arguments to memcpy() are both of type |void*|.  ANSI C++ cannot
change this most basic characteristic of |void*| without breaking
compatibility with many ANSI C programs and large portions of the ANSI
C library.

Point 2: The ARM promises that a |char*| may hold any data address
whatever.  This is guaranteed in the section I quoted in the
referenced article, which asserts that a pointer to any object may be
cast to a pointer to any object of equal or smaller type, and then
back to its original type, without problem.

Conclusion: Since |void*| and |char*| must both be able to hold any
address, the C requirement that they have identical representations is
entirely reasonable for ANSI C++.

>This forces word machines, such as the Cray's, either 1) always create
>slow code ...

Please describe -- exactly -- how |void*|-|char*| equivalence forces
machines with word addressing into generating "slow code".

(Of course, on word-addressed machines, a |T*| is typically only one
word, while a |void*| is larger, to specify the exact byte within the
addressed word.  But that would always be true, regardless of the
implementation of |char*|.)

>But what do I know?

An excellent question.
-- 
Chip Salzenberg at Teltronics/TCT     <chip@tct.uucp>, <uunet!pdn!tct!chip>
 "Most of my code is written by myself.  That is why so little gets done."
                 -- Herman "HLLs will never fly" Rubin