Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > comp.lang.c > #100448
| From | Keith Thompson <kst-u@mib.org> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Octal |
| Date | 2016-12-28 09:59 -0800 |
| Organization | None to speak of |
| Message-ID | <lnwpek3pes.fsf@kst-u.example.com> (permalink) |
| References | (10 earlier) <o3uqga$1g2$1@dont-email.me> <ln37h87udw.fsf@kst-u.example.com> <o3v2hu$qq5$1@dont-email.me> <lntw9o6cr1.fsf@kst-u.example.com> <o407g6$dgp$1@dont-email.me> |
BartC <bc@freeuk.com> writes:
> On 28/12/2016 01:52, Keith Thompson wrote:
>> BartC <bc@freeuk.com> writes:
>> The root of this minor glitch is that 'E' or 'e' can be either a
>> hexadecimal digit *or* it can introduce an exponent in a decimal
>> floating constant.
>
> But this is a hexadecimal one! So there is no conflict.
Yes, there is, as I've explained.
>>> And what would the value of that preprocessing number be?
>>
>> That particular pp-number has no value, either in the sense of a numeric
>> value or of it being useful. Its illegality is just a consequence of
>> the admittedly rather odd rules for handling numeric constants in the
>> preprocessor and in later translation phases, rules that were presumably
>> designed both to make the preprocessor's job easier and to maintain
>> compatibility with existing implementations.
>
> What /is/ the preprocessor's job? As I still don't understand what is
> going on.
Take a look at http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1570.pdf.
6.4.8 discusses preprocessing numbers, and 6.10 discusses preprocessing
directives. 5.1.1.2 describes the 8 translation phases. The
preprocessor's job is to implement phases 1 through 5 or 6 (there's no
definition of which phases are to be implemented by the "preprocessor",
and no requirement for it to be a separate application).
> Are you saying that the sequence "127.0.0.1", which might be parsed in a
> normal language as "127.0", ".0", ".1" (and very likely a syntax error),
> is treated by the pp as one token "127.0.0.1" and passed on to the
> program also as one token "127.0.0.1"?
Yes, I believe I already said that. And at least gcc actually does
that. If I compile a source file containing
double x = 127.0.0.1;
gcc's error message is
c.c:4:16: error: too many decimal points in number
double x = 127.0.0.1;
The form of the message indicates (but doesn't strictly prove) that
127.0.0.1 is treated as a single invalid token, not as a sequence of
tokens (127.0 .0 .1).
> This is contrary to my understanding of how the preprocessor works,
> which is that the output is considered to be text-based, not
> token-based, and the next compilation phase will see the character
> sequence "127.0.0.1" and re-tokenise it whichever way it wants.
Then I guess your understanding differs from what the standard
specifies.
Particular implementations of the C preprocessor *do* commonly generate
output as textual C source code, which is then fed to the remainder of
the compiler for further processing. And that's perfectly valid, as
long as the resulting behavior is consistent with the requirements
implied by the phases of translation. But the standard says that the
source file is decomposed into preprocessing token in phase 3, each of
which is then converted into a single token in phase 7. It says nothing
about how preprocessing tokens and tokens are represented.
> (Wouldn't the output of an early, memory-constrained C preprocessor be
> to file, as text, which is read as text by the next stage?)
Probably. And as long as the behavior is consistent with the
translation phase model, that's perfectly valid.
[...]
--
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"
Back to comp.lang.c | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
Octal BartC <bc@freeuk.com> - 2016-12-27 14:08 +0000
Octal "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-12-27 06:19 -0800
Re: Octal BartC <bc@freeuk.com> - 2016-12-27 14:58 +0000
Re: Octal "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-12-27 07:07 -0800
Re: Octal BartC <bc@freeuk.com> - 2016-12-27 15:22 +0000
Re: Octal "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-12-27 07:37 -0800
Re: Octal BartC <bc@freeuk.com> - 2016-12-27 16:24 +0000
Re: Octal "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-12-27 08:30 -0800
Re: Octal supercat@casperkitty.com - 2016-12-27 09:10 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-27 09:35 -0800
Re: Octal supercat@casperkitty.com - 2016-12-27 10:47 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-27 12:03 -0800
Re: Octal supercat@casperkitty.com - 2016-12-27 12:27 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-27 12:44 -0800
Re: Octal supercat@casperkitty.com - 2016-12-27 13:37 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-27 16:38 -0800
Re: Octal supercat@casperkitty.com - 2016-12-27 17:53 -0800
Re: Octal Robert Wessel <robertwessel2@yahoo.com> - 2016-12-27 20:26 -0600
Re: Octal supercat@casperkitty.com - 2016-12-27 18:48 -0800
Re: Octal Robert Wessel <robertwessel2@yahoo.com> - 2016-12-27 22:20 -0600
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-27 18:41 -0800
Re: Octal supercat@casperkitty.com - 2016-12-27 19:19 -0800
Re: Octal Ian Collins <ian-news@hotmail.com> - 2016-12-29 14:52 +1300
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-28 18:41 -0800
Re: Octal Tim Rentsch <txr@alumni.caltech.edu> - 2016-12-28 16:54 -0800
Re: Octal BartC <bc@freeuk.com> - 2016-12-27 17:44 +0000
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-27 12:17 -0800
Re: Octal BartC <bc@freeuk.com> - 2016-12-27 22:39 +0000
Re: Octal Ian Collins <ian-news@hotmail.com> - 2016-12-28 11:49 +1300
Re: Octal BartC <bc@freeuk.com> - 2016-12-27 23:09 +0000
Re: Octal Ian Collins <ian-news@hotmail.com> - 2016-12-28 12:32 +1300
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 00:51 +0000
Re: Octal Ian Collins <ian-news@hotmail.com> - 2016-12-28 14:00 +1300
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 01:13 +0000
Re: Octal Robert Wessel <robertwessel2@yahoo.com> - 2016-12-27 20:04 -0600
Re: Octal supercat@casperkitty.com - 2016-12-27 18:45 -0800
Re: Octal Tim Rentsch <txr@alumni.caltech.edu> - 2016-12-29 13:35 -0800
Re: Octal supercat@casperkitty.com - 2016-12-29 14:49 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-29 15:33 -0800
Re: Octal supercat@casperkitty.com - 2016-12-30 12:35 -0800
Re: Octal Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-13 15:19 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2017-01-13 15:32 -0800
Re: Octal Ian Collins <ian-news@hotmail.com> - 2017-01-14 12:35 +1300
Re: Octal Keith Thompson <kst-u@mib.org> - 2017-01-13 15:51 -0800
Re: Octal supercat@casperkitty.com - 2017-01-13 18:25 -0800
Re: Octal Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-01-14 06:21 -0800
Re: Octal supercat@casperkitty.com - 2017-01-14 14:00 -0800
Re: Octal Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-15 23:08 -0800
Re: Octal Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-15 23:02 -0800
Re: Octal supercat@casperkitty.com - 2017-01-13 18:52 -0800
Re: Octal Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-15 23:46 -0800
Re: Octal supercat@casperkitty.com - 2017-01-16 01:46 -0800
Re: Octal Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-31 08:33 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-27 17:19 -0800
Re: Octal raltbos@xs4all.nl (Richard Bos) - 2016-12-28 09:39 +0000
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 11:02 +0000
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-28 12:13 +0100
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 11:41 +0000
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-28 09:31 -0800
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 17:39 +0000
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-28 22:05 +0100
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-28 12:01 -0800
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 20:05 +0000
Re: Octal asetofsymbols@gmail.com - 2016-12-28 11:20 -0800
Re: Octal Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-12-28 12:01 +0000
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 12:30 +0000
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-28 13:51 +0100
Re: Octal Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-12-28 16:26 +0000
Re: Octal supercat@casperkitty.com - 2016-12-28 08:40 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-28 09:41 -0800
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 18:04 +0000
Re: Octal Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-12-28 19:36 +0000
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 19:42 +0000
Re: Octal Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-12-29 00:34 +0000
Re: Octal supercat@casperkitty.com - 2016-12-28 11:04 -0800
Re: Octal raltbos@xs4all.nl (Richard Bos) - 2016-12-28 12:09 +0000
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-27 16:46 -0800
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 00:56 +0000
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-27 17:52 -0800
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 11:27 +0000
Re: Octal Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-12-28 12:09 +0000
Re: Octal supercat@casperkitty.com - 2016-12-28 08:17 -0800
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 17:02 +0000
Re: Octal Ike Naar <ike@iceland.freeshell.org> - 2016-12-28 17:25 +0000
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 17:45 +0000
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-28 10:21 -0800
Re: Octal supercat@casperkitty.com - 2016-12-28 09:27 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-28 10:23 -0800
Re: Octal supercat@casperkitty.com - 2016-12-28 11:18 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-28 10:19 -0800
Re: Octal BartC <bc@freeuk.com> - 2016-12-29 15:54 +0000
Re: Octal Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-12-29 12:57 -0800
Re: Octal Ian Collins <ian-news@hotmail.com> - 2016-12-30 10:01 +1300
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-30 10:44 +0100
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-29 17:32 +0100
Re: Octal BartC <bc@freeuk.com> - 2016-12-29 17:03 +0000
Re: Octal Robert Wessel <robertwessel2@yahoo.com> - 2016-12-29 16:26 -0600
Re: Octal Ian Collins <ian-news@hotmail.com> - 2016-12-30 11:31 +1300
Re: Octal Robert Wessel <robertwessel2@yahoo.com> - 2016-12-29 16:58 -0600
Re: Octal Ian Collins <ian-news@hotmail.com> - 2016-12-30 11:59 +1300
Re: Octal Ian Collins <ian-news@hotmail.com> - 2016-12-30 09:00 +1300
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-30 10:21 +0100
Re: Octal asetofsymbols@gmail.com - 2016-12-30 01:29 -0800
Re: Octal asetofsymbols@gmail.com - 2016-12-30 01:29 -0800
Re: Octal asetofsymbols@gmail.com - 2016-12-30 01:36 -0800
Re: Octal BartC <bc@freeuk.com> - 2016-12-29 11:52 +0000
Re: Octal BartC <bc@freeuk.com> - 2016-12-29 17:10 +0000
Re: Octal supercat@casperkitty.com - 2016-12-29 05:52 -0800
Re: Octal Robert Wessel <robertwessel2@yahoo.com> - 2016-12-28 19:51 -0600
Re: Octal BartC <bc@freeuk.com> - 2016-12-29 21:09 +0000
Re: Octal Ian Collins <ian-news@hotmail.com> - 2016-12-30 10:15 +1300
Re: Octal Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-12-29 13:53 -0800
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-30 12:07 +0100
Re: Octal BartC <bc@freeuk.com> - 2016-12-30 13:04 +0000
Re: Octal Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-12-30 05:31 -0800
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-30 15:00 +0100
Re: Octal BartC <bc@freeuk.com> - 2016-12-30 15:55 +0000
Re: Octal David Brown <david.brown@hesbynett.no> - 2017-01-01 16:00 +0100
Re: Octal Ian Collins <ian-news@hotmail.com> - 2017-01-02 08:33 +1300
Re: Octal Ian Collins <ian-news@hotmail.com> - 2017-01-02 09:02 +1300
Re: Octal Ian Collins <ian-news@hotmail.com> - 2017-01-02 09:38 +1300
Re: Octal Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-01-01 13:59 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2017-01-01 14:24 -0800
Re: Octal supercat@casperkitty.com - 2017-01-01 15:51 -0800
Re: Octal Ian Collins <ian-news@hotmail.com> - 2017-01-02 13:09 +1300
Re: Octal supercat@casperkitty.com - 2017-01-01 16:50 -0800
Re: Octal Ian Collins <ian-news@hotmail.com> - 2017-01-02 14:24 +1300
Re: Octal David Brown <david.brown@hesbynett.no> - 2017-01-02 01:53 +0100
Re: Octal Ian Collins <ian-news@hotmail.com> - 2017-01-02 14:15 +1300
Re: Octal Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-02 02:28 -0800
Re: Octal Ian Collins <ian-news@hotmail.com> - 2016-12-31 06:24 +1300
Re: Octal BartC <bc@freeuk.com> - 2016-12-30 17:53 +0000
Re: Octal luser droog <luser.droog@gmail.com> - 2016-12-30 10:01 -0800
Re: Octal Ian Collins <ian-news@hotmail.com> - 2016-12-31 09:57 +1300
Re: Octal supercat@casperkitty.com - 2016-12-30 13:50 -0800
Re: Octal Ian Collins <ian-news@hotmail.com> - 2016-12-31 11:09 +1300
Re: Octal supercat@casperkitty.com - 2016-12-30 14:46 -0800
Re: Octal Ian Collins <ian-news@hotmail.com> - 2016-12-31 12:28 +1300
Re: Octal supercat@casperkitty.com - 2016-12-30 16:01 -0800
Re: Octal Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-12-30 14:48 -0800
Re: Octal BartC <bc@freeuk.com> - 2016-12-30 22:51 +0000
Re: Octal supercat@casperkitty.com - 2016-12-30 15:20 -0800
Re: Octal Ian Collins <ian-news@hotmail.com> - 2016-12-31 12:34 +1300
Re: Octal BartC <bc@freeuk.com> - 2016-12-30 23:40 +0000
Re: Octal BartC <bc@freeuk.com> - 2016-12-30 22:12 +0000
Re: Octal raltbos@xs4all.nl (Richard Bos) - 2016-12-28 21:38 +0000
Re: Octal BartC <bc@freeuk.com> - 2016-12-29 12:04 +0000
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-29 13:42 +0100
Re: Octal Ian Collins <ian-news@hotmail.com> - 2016-12-30 08:59 +1300
Re: Octal supercat@casperkitty.com - 2016-12-29 12:23 -0800
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-30 10:56 +0100
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 22:09 +0000
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-29 12:27 +0100
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 21:18 +0000
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 20:46 +0000
Re: Octal raltbos@xs4all.nl (Richard Bos) - 2016-12-28 20:55 +0000
Re: Octal Robert Wessel <robertwessel2@yahoo.com> - 2016-12-28 14:54 -0600
Re: Octal BartC <bc@freeuk.com> - 2016-12-29 15:44 +0000
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 19:39 +0000
Re: Octal Robert Wessel <robertwessel2@yahoo.com> - 2016-12-28 15:04 -0600
Re: Octal raltbos@xs4all.nl (Richard Bos) - 2016-12-28 19:52 +0000
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-29 09:36 -0800
Re: Octal BartC <bc@freeuk.com> - 2016-12-29 18:02 +0000
Re: Octal BartC <bc@freeuk.com> - 2016-12-30 16:17 +0000
Re: Octal David Brown <david.brown@hesbynett.no> - 2017-01-01 16:09 +0100
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 20:02 +0000
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-28 12:32 -0800
Re: Octal Richard Heathfield <rjh@cpax.org.uk> - 2016-12-29 13:45 +0000
Re: Octal Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-12-28 17:16 +0000
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-28 10:04 -0800
Re: Octal Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-02 02:26 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2017-01-02 12:35 -0800
Re: Octal Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-12 23:22 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2017-01-13 10:04 -0800
Re: Octal Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-14 00:45 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-28 09:59 -0800
Re: Octal "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-12-27 09:45 -0800
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-27 17:14 +0100
Re: Octal "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-12-27 08:23 -0800
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-28 10:37 +0100
Re: Octal "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-12-28 03:07 -0800
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-28 12:25 +0100
Re: Octal Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-12-28 11:58 +0000
Re: Octal "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-12-28 04:35 -0800
Re: Octal Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-12-28 17:31 +0000
Re: Octal "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-12-28 09:38 -0800
Re: Octal Robert Wessel <robertwessel2@yahoo.com> - 2016-12-28 15:12 -0600
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-28 12:01 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-28 09:20 -0800
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-28 13:39 -0800
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-29 12:29 +0100
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-28 22:20 +0100
Re: Octal Noob <root@127.0.0.1> - 2016-12-28 13:02 +0100
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-28 13:30 +0100
Re: Octal BartC <bc@freeuk.com> - 2016-12-28 13:25 +0000
Re: Octal Manfred <noname@invalid.add> - 2016-12-27 15:19 +0100
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-27 08:37 -0800
Re: Octal Manfred <noname@invalid.add> - 2016-12-27 18:43 +0100
Re: Octal Keith Thompson <kst-u@mib.org> - 2016-12-27 12:07 -0800
Re: Octal Manfred <noname@invalid.add> - 2016-12-27 18:21 +0100
Re: Octal David Brown <david.brown@hesbynett.no> - 2016-12-27 15:28 +0100
Re: Octal BGB <cr88192@hotmail.com> - 2016-12-27 11:42 -0600
csiph-web