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From: Tim Rentsch <tr.17687@z991.linuxsc.com>
Newsgroups: comp.lang.c
Subject: Re: Const-qualified function return type in C - is it a part of function type?
Date: Mon, 24 Feb 2020 21:06:41 -0800
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Ben Bacarisse <ben.usenet@bsb.me.uk> writes:

> luser droog <luser.droog@gmail.com> writes:
>
>> On Saturday, February 22, 2020 at 8:22:18 AM UTC-6, Ben Bacarisse wrote:
>>
>>> Andrey Tarasevich <andreytarasevich@hotmail.com> writes:
>>> <cut>
>>>
>>>> To avoid any further wastage of time on this irrelevant matter I
>>>> hereby postulate one more time:  the above quoted passage refers to
>>>> qualifiers applied to the function type itself (which, BTW, is only
>>>> possible through typedef names).
>>>
>>> And interesting detail, which I can't interpret...  In all versions of
>>> the C standard, there is a footnote attached to the paragraph
>>>
>>>   "If the specification of an array type includes any type qualifiers,
>>>   the element type is so qualified, not the array type.  If the
>>>   specification of a function type includes any type qualifiers, the
>>>   behavior is undefined."
>>>
>>> In C90, this footnote seems to be:
>>>
>>>   59) Both of these can only occur through the use of typedefs.
>>>
>>> By C99 it appears to have become
>>>
>>>   118) Both of these can occur through the use of typedefs.
>>>
>>> Why the change I wonder?  Is there a way to qualify a function or array
>>> type without a typedef?  I can't see one.
>>
>> What about using parens?
>
> I don't think you can.  I tried.

I concur with Ben here.

>> int (const sammy[2]);
>
> I think int (const sammy)[2]; would be closer (were it allowed) because
> parentheses in a declarator are there to stop you reading in the
> "default" direction -- to the right.  Reading what you wrote, you'd say
> "sammy is an array of 2 const int".
>
>> float (volatile davis)(void);
>
> That's the way it would be written, but you can't do that as far as I
> can see.

If we are looking for an extension to supply the capability, how
about this way:

    int sammy const [2];
    float davis volatile (void);

I note with some amusement that C++ made a different choice, for
member functions:

    int x_value() const;

Of course the meaning of "const" here isn't quite the same as
the "const" we are used to, but it does modify the function
type itself:  they are commonly (or officially?) called
"const member functions".