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From: Keith Thompson <kst-u@mib.org>
Newsgroups: comp.lang.c
Subject: Re: pointers
Date: Mon, 24 Oct 2016 12:22:43 -0700
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supercat@casperkitty.com writes:
> On Monday, October 24, 2016 at 11:52:05 AM UTC-5, Keith Thompson wrote:
>> So the only reason you can think of to use those constructs is to
>> illustrate them?  That's hardly a good reason to add them to the
>> language.
>
> Especially on implementations where all pointers have the same representation
> and are alias-compatible with void*, it would be helpful to have a means by
> which a macro that wraps a function call could ensure that it is given a
> double-indirect pointer to some kind of object.  If the final target type
> were required to be something other than "void", such a macro could perhaps
> use:
>
>     foo(sizeof(**(theHandle)) >= 0 ? (void**)(theHandle) : 0));
>
> Since sizeof would not evaluate its operand, that would only cause theHandle
> to be evaluated once.  I can't think of any other way, though, to write a
> macro which would cast its argument to void** in the event that it was any
> kind of double-indirect pointer, but would squawk if it were anything else.

How is that relevant?  BartC is talking about constructs that are not
valid in C.  

(Of course void** is not a generic pointer-to-pointer type.)

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something.  This is something.  Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"