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Groups > comp.lang.c > #112694
| From | Keith Thompson <kst-u@mib.org> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Null pointer constant |
| Date | 2017-06-20 08:43 -0700 |
| Organization | None to speak of |
| Message-ID | <lny3smd5qx.fsf@kst-u.example.com> (permalink) |
| References | (8 earlier) <87shiwc4il.fsf@bsb.me.uk> <oi9cf4$q9s$1@dont-email.me> <878tknd6ow.fsf@bsb.me.uk> <lntw3bekkp.fsf@kst-u.example.com> <kfnwp876wj5.fsf@x-alumni2.alumni.caltech.edu> |
Tim Rentsch <txr@alumni.caltech.edu> writes:
> Keith Thompson <kst-u@mib.org> writes:
>> Ben Bacarisse <ben.usenet@bsb.me.uk> writes:
>>> David Brown <david.brown@hesbynett.no> writes:
>> [...]
>>
>>>> My own knowledge here was enough for my own uses - if you never write
>>>> "(a, b, 0)" then you don't need to know if it is a null pointer
>>>> constant or not :-)
>>>
>>> Just avoid any confusion: it isn't -- ever. It can't even be a constant
>>> expression. I should have been more careful.
>>
>> Except that (6.6p10):
>> An implementation may accept other forms of constant expressions.
>
> That's true, but it's sort of a moot point. Using '(a, b, 0)' as a
> constant expression requires a diagnostic (because a constraint has
> been violated), and after giving a diagnostic the implementation
> can do as it damn well pleases anyway.
One could argue that the intent is that an implementation may
accept other forms of constant expression *without a diagnostic*.
If not, 6.6p10 "An implementation may accept other forms of
constant expressions." would seem to be redundant, since it's
already covered by the permission to provide extensions.
If we follow what the standard actually says, the constraint in
paragraph 3 is uncondtional, and a diagnostic is required.
I'm not sure what the purpose of that added permission really is.
Do you know whether the authors had anything specific in mind?
--
Keith Thompson (The_Other_Keith) kst-u@mib.org <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"
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Null pointer constant bartc <bc@freeuk.com> - 2017-06-18 17:15 +0100
Re: Null pointer constant Keith Thompson <kst-u@mib.org> - 2017-06-18 11:20 -0700
Re: Null pointer constant Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-06-18 19:23 +0100
Re: Null pointer constant bartc <bc@freeuk.com> - 2017-06-18 20:57 +0100
Re: Null pointer constant Keith Thompson <kst-u@mib.org> - 2017-06-18 13:38 -0700
Re: Null pointer constant Tim Rentsch <txr@alumni.caltech.edu> - 2017-06-19 04:35 -0700
Re: Null pointer constant Nick Bowler <nbowler@draconx.ca> - 2017-06-19 18:08 +0000
Re: Null pointer constant Tim Rentsch <txr@alumni.caltech.edu> - 2017-06-19 21:05 -0700
Re: Null pointer constant Keith Thompson <kst-u@mib.org> - 2017-06-19 12:12 -0700
Re: Null pointer constant Tim Rentsch <txr@alumni.caltech.edu> - 2017-06-19 21:08 -0700
Re: Null pointer constant Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-06-19 00:34 +0100
Re: Null pointer constant Tim Rentsch <txr@alumni.caltech.edu> - 2017-06-19 04:45 -0700
Re: Null pointer constant David Brown <david.brown@hesbynett.no> - 2017-06-19 13:55 +0200
Re: Null pointer constant bartc <bc@freeuk.com> - 2017-06-19 13:16 +0100
Re: Null pointer constant Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-06-19 16:58 +0100
Re: Null pointer constant Ike Naar <ike@iceland.freeshell.org> - 2017-06-18 20:58 +0000
Re: Null pointer constant bartc <bc@freeuk.com> - 2017-06-19 00:11 +0100
Re: Null pointer constant David Brown <david.brown@hesbynett.no> - 2017-06-19 03:21 +0200
Re: Null pointer constant bartc <bc@freeuk.com> - 2017-06-19 10:11 +0100
Re: Null pointer constant David Brown <david.brown@hesbynett.no> - 2017-06-19 12:38 +0200
Re: Null pointer constant bartc <bc@freeuk.com> - 2017-06-19 13:05 +0100
Re: Null pointer constant David Brown <david.brown@hesbynett.no> - 2017-06-19 14:39 +0200
Re: Null pointer constant "James R. Kuyper" <jameskuyper@verizon.net> - 2017-06-19 11:06 -0400
Re: Null pointer constant Ike Naar <ike@iceland.freeshell.org> - 2017-06-19 15:51 +0000
Re: Null pointer constant "James R. Kuyper" <jameskuyper@verizon.net> - 2017-06-19 12:22 -0400
Re: Null pointer constant Ike Naar <ike@iceland.freeshell.org> - 2017-06-19 17:29 +0000
Re: Null pointer constant "James R. Kuyper" <jameskuyper@verizon.net> - 2017-06-19 13:45 -0400
Re: Null pointer constant Keith Thompson <kst-u@mib.org> - 2017-06-19 12:31 -0700
Re: Null pointer constant Ike Naar <ike@iceland.freeshell.org> - 2017-06-19 15:10 +0000
Re: Null pointer constant Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-06-19 16:53 +0100
Re: Null pointer constant "James R. Kuyper" <jameskuyper@verizon.net> - 2017-06-19 13:06 -0400
Re: Null pointer constant Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-06-19 20:03 +0100
Re: Null pointer constant David Brown <david.brown@hesbynett.no> - 2017-06-19 22:37 +0200
Re: Null pointer constant Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-06-19 22:10 +0100
Re: Null pointer constant Keith Thompson <kst-u@mib.org> - 2017-06-19 14:25 -0700
Re: Null pointer constant Tim Rentsch <txr@alumni.caltech.edu> - 2017-06-19 22:46 -0700
Re: Null pointer constant Keith Thompson <kst-u@mib.org> - 2017-06-20 08:43 -0700
Re: Null pointer constant supercat@casperkitty.com - 2017-06-20 09:17 -0700
Re: Null pointer constant Tim Rentsch <txr@alumni.caltech.edu> - 2017-06-21 00:56 -0700
Re: Null pointer constant Keith Thompson <kst-u@mib.org> - 2017-06-21 10:07 -0700
Re: Null pointer constant Tim Rentsch <txr@alumni.caltech.edu> - 2017-06-21 23:52 -0700
Re: Null pointer constant Keith Thompson <kst-u@mib.org> - 2017-06-22 10:12 -0700
Re: Null pointer constant Tim Rentsch <txr@alumni.caltech.edu> - 2017-06-22 17:33 -0700
Re: Null pointer constant supercat@casperkitty.com - 2017-06-23 08:54 -0700
Re: Null pointer constant Manfred <invalid@invalid.add> - 2017-06-20 00:00 +0200
Re: Null pointer constant Keith Thompson <kst-u@mib.org> - 2017-06-19 15:27 -0700
Re: Null pointer constant supercat@casperkitty.com - 2017-06-19 16:38 -0700
Re: Null pointer constant Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-06-20 01:14 +0100
Re: Null pointer constant Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-06-20 12:03 +0100
Re: Null pointer constant Manfred <noname@invalid.add> - 2017-06-20 13:16 +0200
Re: Null pointer constant jameskuyper@verizon.net - 2017-06-20 05:34 -0700
Re: Null pointer constant Keith Thompson <kst-u@mib.org> - 2017-06-20 08:49 -0700
Re: Null pointer constant Ike Naar <ike@iceland.freeshell.org> - 2017-06-20 16:35 +0000
Re: Null pointer constant "James R. Kuyper" <jameskuyper@verizon.net> - 2017-06-20 13:07 -0400
Re: Null pointer constant Nick Bowler <nbowler@draconx.ca> - 2017-06-20 17:29 +0000
Re: Null pointer constant "James R. Kuyper" <jameskuyper@verizon.net> - 2017-06-20 13:55 -0400
Re: Null pointer constant Nick Bowler <nbowler@draconx.ca> - 2017-06-20 18:06 +0000
Re: Null pointer constant "James R. Kuyper" <jameskuyper@verizon.net> - 2017-06-20 14:42 -0400
Re: Null pointer constant Nick Bowler <nbowler@draconx.ca> - 2017-06-20 19:10 +0000
Re: Null pointer constant Ike Naar <ike@iceland.freeshell.org> - 2017-06-20 18:31 +0000
Re: Null pointer constant Nick Bowler <nbowler@draconx.ca> - 2017-06-20 18:36 +0000
Re: Null pointer constant "James R. Kuyper" <jameskuyper@verizon.net> - 2017-06-20 14:45 -0400
Re: Null pointer constant Nick Bowler <nbowler@draconx.ca> - 2017-06-20 17:14 +0000
Re: Null pointer constant Keith Thompson <kst-u@mib.org> - 2017-06-20 11:55 -0700
Re: Null pointer constant Nick Bowler <nbowler@draconx.ca> - 2017-06-20 19:23 +0000
Re: Null pointer constant "James R. Kuyper" <jameskuyper@verizon.net> - 2017-06-20 15:39 -0400
Re: Null pointer constant scott@slp53.sl.home (Scott Lurndal) - 2017-06-21 13:44 +0000
Re: Null pointer constant scott@slp53.sl.home (Scott Lurndal) - 2017-06-21 13:49 +0000
Re: Null pointer constant Tim Rentsch <txr@alumni.caltech.edu> - 2017-06-21 23:57 -0700
Re: Null pointer constant Philip Lantz <prl@canterey.us> - 2017-06-28 20:04 -0700
Re: Null pointer constant Tim Rentsch <txr@alumni.caltech.edu> - 2017-07-10 08:38 -0700
Re: Null pointer constant Keith Thompson <kst-u@mib.org> - 2017-06-20 12:39 -0700
Re: Null pointer constant bartc <bc@freeuk.com> - 2017-06-20 20:53 +0100
Re: Null pointer constant Keith Thompson <kst-u@mib.org> - 2017-06-20 13:07 -0700
Re: Null pointer constant Nick Bowler <nbowler@draconx.ca> - 2017-06-20 20:50 +0000
Re: Null pointer constant Keith Thompson <kst-u@mib.org> - 2017-06-20 15:35 -0700
Re: Null pointer constant Tim Rentsch <txr@alumni.caltech.edu> - 2017-06-21 00:26 -0700
Re: Null pointer constant Keith Thompson <kst-u@mib.org> - 2017-06-21 09:54 -0700
Re: Null pointer constant "James R. Kuyper" <jameskuyper@verizon.net> - 2017-06-21 13:09 -0400
Re: Null pointer constant Tim Rentsch <txr@alumni.caltech.edu> - 2017-06-22 00:53 -0700
Re: Null pointer constant bartc <bc@freeuk.com> - 2017-06-21 18:09 +0100
Re: Null pointer constant Tim Rentsch <txr@alumni.caltech.edu> - 2017-06-22 00:50 -0700
Re: Null pointer constant Keith Thompson <kst-u@mib.org> - 2017-06-19 10:24 -0700
Re: Null pointer constant Tim Rentsch <txr@alumni.caltech.edu> - 2017-06-19 22:32 -0700
Re: Null pointer constant bartc <bc@freeuk.com> - 2017-06-19 19:40 +0100
Re: Null pointer constant Keith Thompson <kst-u@mib.org> - 2017-06-19 12:08 -0700
Re: Null pointer constant bartc <bc@freeuk.com> - 2017-06-19 20:32 +0100
Re: Null pointer constant Keith Thompson <kst-u@mib.org> - 2017-06-19 12:48 -0700
Re: Null pointer constant jameskuyper@verizon.net - 2017-06-19 13:08 -0700
Re: Null pointer constant Nick Bowler <nbowler@draconx.ca> - 2017-06-19 20:40 +0000
Re: Null pointer constant bartc <bc@freeuk.com> - 2017-06-19 22:01 +0100
Re: Null pointer constant supercat@casperkitty.com - 2017-06-19 14:15 -0700
Re: Null pointer constant jameskuyper@verizon.net - 2017-06-19 14:25 -0700
Re: Null pointer constant Ike Naar <ike@iceland.freeshell.org> - 2017-06-19 21:06 +0000
Re: Null pointer constant Keith Thompson <kst-u@mib.org> - 2017-06-19 14:28 -0700
Re: Null pointer constant Ike Naar <ike@iceland.freeshell.org> - 2017-06-19 21:35 +0000
Re: Null pointer constant supercat@casperkitty.com - 2017-06-19 14:48 -0700
Re: Null pointer constant Ike Naar <ike@iceland.freeshell.org> - 2017-06-20 15:38 +0000
Re: Null pointer constant Keith Thompson <kst-u@mib.org> - 2017-06-19 15:16 -0700
Re: Null pointer constant supercat@casperkitty.com - 2017-06-19 14:29 -0700
Re: Null pointer constant Keith Thompson <kst-u@mib.org> - 2017-06-19 15:18 -0700
Re: Null pointer constant Tim Rentsch <txr@alumni.caltech.edu> - 2017-06-19 22:48 -0700
Re: Null pointer constant bartc <bc@freeuk.com> - 2017-06-20 15:09 +0100
Re: Null pointer constant Keith Thompson <kst-u@mib.org> - 2017-06-19 10:19 -0700
Re: Null pointer constant Keith Thompson <kst-u@mib.org> - 2017-06-19 10:15 -0700
Re: Null pointer constant David Brown <david.brown@hesbynett.no> - 2017-06-19 22:44 +0200
Re: Null pointer constant Keith Thompson <kst-u@mib.org> - 2017-06-19 12:24 -0700
Re: Null pointer constant Ike Naar <ike@iceland.freeshell.org> - 2017-06-19 08:21 +0000
Re: Null pointer constant bartc <bc@freeuk.com> - 2017-06-19 10:17 +0100
Re: Null pointer constant Keith Thompson <kst-u@mib.org> - 2017-06-19 10:04 -0700
Re: Null pointer constant Keith Thompson <kst-u@mib.org> - 2017-06-19 12:34 -0700
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