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From: Ben Bacarisse <ben@bsb.me.uk>
Newsgroups: comp.lang.c
Subject: Re: technology discussion =?utf-8?Q?=E2=86=92?= does the world need
 a "new" C ?
Date: Mon, 19 Aug 2024 02:30:15 +0100
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Bart <bc@freeuk.com> writes:

> On 19/08/2024 01:01, Ben Bacarisse wrote:
>> Bart <bc@freeuk.com> writes:
>> 
>
>>> You or he would have to go into more detail, such as an actual example, to
>>> demonstrate whatever it is that you think is wrong about passing a pointer
>>> argument by-reference.
>> No one has said any such thing, so I can't see how any more detail could
>> help.  I suspect you've lost track of the point being made.
>
> Probably, and perhaps not just me! But I'd still quite like to know exactly
> what it is that is marked as 'disallowed'.

I don't know how to explain it any better.  If you really want to know,
maybe you could say what /you/ think was incorrectly marked as
disallowed so I can see how you were interpreting the table.  You
obviously had something in mind or you could not have said Tim was
wrong.

>>>> I can't unravel this.  Take, as a concrete example, C++.  You can't pass
>>>> a pointer to function that takes an array passed by reference.  You can,
>>>> of course, pass a pointer by reference, but that is neither here nor
>>>> there.
>>>
>>> OK. So why do you agree with this:
>>>
>>>>>>>>                             C call-by-value         call-by-reference
>>>>>>>>                             ===============         =================
>>>>>>>>         (pointer argument)  F(p)                    (disallowed)
>>>
>>> What is 'pointer argument' here?
>> I can't see what is confusing you about this.  I agree with the above
>> for exactly the reasons I wrote.
>
> Do you mean: 'You can't pass a pointer to a function that takes an array
> passed by reference'?

Yes.  As you say below, there would be a good reason not to allow that
in a C-like language with call-by reference added.

>> It would be wrong (and is wrong in
>> C++) to pass a pointer where an array reference is expected.
>
> Well, putting aside pass-by-reference, that would be wrong in C too, if you
> interpret 'array reference' to be a type like T(*)[], and a 'pointer' a
> type like T*.

I'm not sure what this true remark adds.  Everything that is in
discussion relates to call-by-reference where that clearly does not just
mean "passing a pointer".

> With pass-by-reference added to C, there would be stronger type checking,
> so if something is disallowed, it would be for a good reason, not just
> because Tim said so.

Or maybe, just maybe, Tim said it for good reason.

-- 
Ben.