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Re: Call to a function

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Keith Thompson <Keith.S.Thompson+u@gmail.com> writes:

> The code we're discussing was snipped at some point, so here it
> is again:
>
> int main(void) {
>     int obj = 42;
>     typedef void func(void);
>     if (0) {
>         func *fptr = (func*)&obj;
>         fptr();
>     }
> }
>
> It illustrates the issue that the standard does not define the behavior
> of a conversion from an object pointer type to a function pointer type
> (other than the special case of a null pointer constant), but does not
> make such conversion, expressed as a cast, a constraint violation.
>
> I asked:  "On what basis do you think a conforming implementation may
> reject it?

The code is not strictly conforming.

> Do you see a syntax rule or constraint that it violates?

No.

> Do you see some other basis for rejecting it?"

Yes.  The conversion expression can be untranslatable on some
platforms.  That means any such expression cannot be part of
a strictly conforming program.

> To be clear, I'm asking about whether an implementation may reject it
> specifically because of the pointer conversion, not about reasons for
> rejecting it that would apply equally to a "hello, world" program.

It is the pointer conversion expression that makes the program be
not strictly conforming.

> Feel free to disregard the following paragraphs.
>
> The impression I get (very likely a wrong one) is that you are
> trying to use a Socratic method,

I'm not.

> asking me questions that you
> think will steer me to the correct conclusion -- a conclusion that
> you have not shared.  I am not speculating about your motivations
> (which you hide very well); rather, I am letting you know about the
> impression that I get from what you write.  I'm interested in what
> you think about relevant technical issues, but I'm not interested
> in playing the role of your student.

I have no interest in treating you as a student.  I'd be much
happier if you would do more thinking for yourself.

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Re: Call to a function Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-10-29 05:47 -0700
  Re: Call to a function Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-10-29 14:40 -0700
    Re: Call to a function Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-11-10 06:33 -0800
    Re: Call to a function Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-11-17 21:16 -0800
    Re: Call to a function Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-11-19 00:09 -0800
      Re: Call to a function Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-11-19 13:20 -0800
        Re: Call to a function Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-01-19 12:49 -0800
          Re: Call to a function Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-01-22 03:27 +0000
            Re: Call to a function Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-01-21 20:14 -0800
            Re: Call to a function scott@slp53.sl.home (Scott Lurndal) - 2024-01-22 16:36 +0000
              Re: Call to a function Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-01-22 22:05 +0000
    Re: Call to a function James Kuyper <jameskuyper@alumni.caltech.edu> - 2023-11-19 18:50 -0500
      Re: Call to a function Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-01-22 18:11 -0800
      Re: Call to a function James Kuyper <jameskuyper@alumni.caltech.edu> - 2024-01-23 14:19 -0500

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