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Groups > comp.lang.c > #384077
| From | Keith Thompson <Keith.S.Thompson+u@gmail.com> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Casting the return value of ... |
| Date | 2024-03-28 15:37 -0700 |
| Organization | None to speak of |
| Message-ID | <877chmt23h.fsf@nosuchdomain.example.com> (permalink) |
| References | (1 earlier) <20240328105203.773@kylheku.com> <87frwatadu.fsf@nosuchdomain.example.com> <uu4k1c$3pq71$1@dont-email.me> <87bk6yt68v.fsf@nosuchdomain.example.com> <20240328142950.542@kylheku.com> |
Kaz Kylheku <433-929-6894@kylheku.com> writes:
> On 2024-03-28, Keith Thompson <Keith.S.Thompson+u@gmail.com> wrote:
>> The warnings I get from gcc are:
>>
>> warning: ISO C forbids conversion of function pointer to object pointer type [-Wpedantic]
>> warning: ISO C forbids conversion of object pointer to function pointer type [-Wpedantic]
>>
>> With -pedantic-errors, these become fatal errors.
>>
>> I disagree with gcc. ISO C doesn't define the behavior, but it doesn't
>> forbid the conversion.
>
> It's never good for a diagnostic to be stating a blatant falsehood,
> regardless of whether the presence of the diagnostic is a good idea
> or not.
[...]
> I'm actually opening a GCC bugzilla about this right now.
I should have remembered that I reported this as a bug in 2017:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83584
That bug report was closed (inappropriately IMHO) as a duplicate of
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=11234
A commenter on bug #83584 cites the C99 Rationale:
"Even with an explicit cast, it is invalid to convert a function pointer
to an object pointer or a pointer to void, or vice versa."
It's not clear what "invalid" means in that context, and in any case the
Rationale is not normative.
N1570 Annex J 5.7 mentions casting between object pointers and function
pointers as a common extension.
Kaz, I see you've submitted
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114526
which has (inappropriately IMHO) been closed as a duplicate of #11234.
--
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
Working, but not speaking, for Medtronic
void Void(void) { Void(); } /* The recursive call of the void */
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Casting the return value of ... gazelle@shell.xmission.com (Kenny McCormack) - 2024-03-28 15:09 +0000
Re: Casting the return value of ... Kaz Kylheku <433-929-6894@kylheku.com> - 2024-03-28 18:16 +0000
Re: Casting the return value of ... scott@slp53.sl.home (Scott Lurndal) - 2024-03-28 18:53 +0000
Re: Casting the return value of ... Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-30 10:33 -0700
Re: Casting the return value of ... scott@slp53.sl.home (Scott Lurndal) - 2024-03-30 19:29 +0000
Re: Casting the return value of ... Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-03-30 23:05 +0000
Re: Casting the return value of ... scott@slp53.sl.home (Scott Lurndal) - 2024-03-30 23:25 +0000
Re: Casting the return value of ... David Brown <david.brown@hesbynett.no> - 2024-03-31 15:44 +0200
Re: Casting the return value of ... "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-03-31 13:15 -0700
Re: Casting the return value of ... Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-04-08 23:01 -0700
Re: Casting the return value of ... David Brown <david.brown@hesbynett.no> - 2024-04-09 10:03 +0200
Re: Casting the return value of ... Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-03-28 12:38 -0700
Re: Casting the return value of ... bart <bc@freeuk.com> - 2024-03-28 20:30 +0000
Re: Casting the return value of ... Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-03-28 14:07 -0700
Re: Casting the return value of ... "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-03-28 14:15 -0700
Re: Casting the return value of ... Kaz Kylheku <433-929-6894@kylheku.com> - 2024-03-28 21:44 +0000
Re: Casting the return value of ... Kaz Kylheku <433-929-6894@kylheku.com> - 2024-03-28 22:01 +0000
Re: Casting the return value of ... Kaz Kylheku <433-929-6894@kylheku.com> - 2024-03-28 22:33 +0000
Re: Casting the return value of ... Michael S <already5chosen@yahoo.com> - 2024-03-29 15:53 +0200
gcc Bugzilla search (was: Casting the return value of ...) Michael S <already5chosen@yahoo.com> - 2024-03-29 16:01 +0200
Re: gcc Bugzilla search David Brown <david.brown@hesbynett.no> - 2024-03-29 17:00 +0100
Re: Casting the return value of ... Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-03-28 15:37 -0700
Re: Casting the return value of ... Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-06-07 21:23 -0700
Re: Casting the return value of ... David Brown <david.brown@hesbynett.no> - 2024-03-29 14:06 +0100
Re: Casting the return value of ... "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-03-29 15:46 -0700
Re: Casting the return value of ... David Brown <david.brown@hesbynett.no> - 2024-03-29 13:58 +0100
Re: Casting the return value of ... bart <bc@freeuk.com> - 2024-03-29 13:32 +0000
Re: Casting the return value of ... David Brown <david.brown@hesbynett.no> - 2024-03-29 17:10 +0100
Re: Casting the return value of ... Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-30 02:32 -0700
Re: Casting the return value of ... bart <bc@freeuk.com> - 2024-03-30 11:14 +0000
Re: Casting the return value of ... Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-04-08 23:41 -0700
Re: Casting the return value of ... Andrey Tarasevich <andreytarasevich@hotmail.com> - 2024-03-28 21:41 -0700
Re: Casting the return value of ... Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-03-28 22:02 -0700
Re: Casting the return value of ... Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-29 15:52 -0700
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