Re: technology discussion → does the world need a "new" C ?

Ben Bacarisse <ben@bsb.me.uk> writes:

David Brown <david.brown@hesbynett.no> writes:
>

On 16/08/2024 12:00, Ben Bacarisse wrote:
>

David Brown <david.brown@hesbynett.no> writes:
>

On 16/08/2024 02:08, Ben Bacarisse wrote:
>

Bart <bc@freeuk.com> writes:
>

In general there is no reason, in a language with true
call-by-reference, why any parameter type T (which has the form
U*, a pointer to anything), cannot be passed by reference.  It
doesn't matter whether U is an array type or not.

>
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.

>
In C++, you can't pass arrays as parameters at all - the language
inherited C's handling of arrays.  You can, of course, pass
objects of std::array<> type by value or by reference, just like
any other class types.

>
The best way to think about C++ (in my very non-expert opinion) is
to consider references as values that are passed by, err...,
value.  But you seem prepared to accept that some things can be
"passed by reference" in C++.

>
That seems a subtle distinction - I'll have to think about it a
little.  I like your description of arguments being like local
variable initialisation - it makes sense equally well regardless of
whether the parameter is "int", "int*", or "int&".  (It's probably
best not to mention the other one in this group...)
>

So if this:
#include <iostream>
void g(int &i) { std::cout << i << "\n"; }
int main(void)
{
    int I{0};
    g(I);
}
shows an int object, I, being passed to g, why does this
#include <iostream>
void f(int (&ar)[10]) { std::cout << sizeof ar << "\n"; }
int main(void)
{
    int A[10];
    f(A);
}
not show an array, A, being passed to f?

>
That's backwards compatibility with C array handling at play.

>
I'm not sure how this answers my question.  Maybe you weren't
answering it and were just making a remark...

My guess is he didn't understand the question.  The code shown
has nothing to do with backwards compatibility with C array
handling.