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Groups > comp.lang.c > #142313
| From | Tim Rentsch <tr.17687@z991.linuxsc.com> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: [ On topic, amazingtly ]: labels and declarations |
| Date | 2019-03-23 13:36 -0700 |
| Organization | A noiseless patient Spider |
| Message-ID | <8636ndnxaa.fsf@mailhub.linuxsc.com> (permalink) |
| References | (4 earlier) <q70f9c$ar7$1@gioia.aioe.org> <7164203b-a47f-4120-a6d0-c3a6b659a738@googlegroups.com> <q73589$eob$1@dont-email.me> <lnk1gqg3re.fsf@kst-u.example.com> <q75nnt$1ivd$1@gioia.aioe.org> |
Manfred <noname@add.invalid> writes:
> On 3/22/2019 7:31 PM, Keith Thompson wrote:
>
>> Manfred <invalid@add.invalid> writes:
>> [...]
>>
>>> The standard allows for some optional features, enabled by preprocessor
>>> definitions. This implies that functionality provided by the standard
>>> library can be made optional, but features of the language itself cannot.
>>> So, for this case, the semantics of a C label, this would not work.
>>
>> [...]
>>
>> No, language features can be and are made optional. In C11, complex
>> numbers, atomic types, complex types, and VLAs, among other things,
>> are optional, and each has a corresponding predefined macro that
>> indicates whether the implementation supports it. See C11/N1570
>> 6.10.8.3.
>
> That's not what I meant: the macros you refer to are defined by the
> implementation to indicate whether the implementation supports such
> language features. They are not meant for the programmer to #define or
> #undef to switch such features on/off.
>
> Instead, when I wrote the post I had in mind macros like
> _USE_MATH_DEFINES that enables #define's of stuff like M_PI, but later
> I realized that this is not part of the ISO standard, so I was
> probably wrong with the part of the standard allowing for such
> customization via preprocessor definitions (selectable by the
> programmer, not the implementation).
ISO C does have a standard mechanism whereby programs can direct
an implementation to alter the source language in some way, and
which could be used to cause preprocessor changes like #define'ing
M_PI, or other things. The mechanism is #pragma. In current C
there are, IIRC, only three standardized #pragma's (those being
CX_LIMITED_RANGE, FENV_ACCESS, and FP_CONTRACT, all under #pragma
STDC), but others could be added to control code behavior
semantics, what symbols are defined by which standard header
files, or even what source language constructs are allowed. So an
option to allow labels on declarations could be provided, as for
example
#pragma STDC DECLARATIONS_MAY_HAVE_LABELS ON
which would fit easily into the existing ISO standard. Of course,
implementing such things might be a nightmare, but there is an
"ISO C normal" way of specifying them.
(Please note that I am not suggesting that this /should/ be done,
only that it /could/ be done.)
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[ On topic, amazingtly ]: labels and declarations gazelle@shell.xmission.com (Kenny McCormack) - 2019-03-17 14:45 +0000
Re: [ On topic, amazingtly ]: labels and declarations nobody@example.org (Scott) - 2019-03-17 17:25 +0000
Re: [ On topic, amazingtly ]: labels and declarations fir is a sexy shemale <cdalten@gmail.com> - 2019-03-17 10:59 -0700
Re: [ On topic, amazingtly ]: labels and declarations Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2019-03-17 14:16 -0400
Re: [ On topic, amazingtly ]: labels and declarations Richard Damon <Richard@Damon-Family.org> - 2019-03-17 18:43 -0400
Re: [ On topic, amazingtly ]: labels and declarations Bart <bc@freeuk.com> - 2019-03-17 22:55 +0000
Re: [ On topic, amazingtly ]: labels and declarations Bart <bc@freeuk.com> - 2019-03-18 01:37 +0000
Re: [ On topic, amazingtly ]: labels and declarations Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-03-17 19:46 -0700
Re: [ On topic, amazingtly ]: labels and declarations David Brown <david.brown@hesbynett.no> - 2019-03-18 08:41 +0100
Re: [ On topic, amazingtly ]: labels and declarations Bart <bc@freeuk.com> - 2019-03-18 11:20 +0000
Re: [ On topic, amazingtly ]: labels and declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-18 04:39 -0700
Re: [ On topic, amazingtly ]: labels and declarations Bart <bc@freeuk.com> - 2019-03-18 12:08 +0000
Re: [ On topic, amazingtly ]: labels and declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-18 05:26 -0700
labels and declarations and debugger breakpoints "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-18 05:40 -0700
Re: [ On topic, amazingtly ]: labels and declarations Bart <bc@freeuk.com> - 2019-03-18 17:25 +0000
Re: [ On topic, amazingtly ]: labels and declarations gazelle@shell.xmission.com (Kenny McCormack) - 2019-03-18 19:11 +0000
Re: [ On topic, amazingtly ]: labels and declarations Bart <bc@freeuk.com> - 2019-03-19 01:36 +0000
Re: [ On topic, amazingtly ]: labels and declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-18 12:31 -0700
Re: [ On topic, amazingtly ]: labels and declarations Bart <bc@freeuk.com> - 2019-03-18 19:57 +0000
Re: [ On topic, amazingtly ]: labels and declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-18 13:09 -0700
Re: [ On topic, amazingtly ]: labels and declarations Bart <bc@freeuk.com> - 2019-03-18 21:09 +0000
Re: [ On topic, amazingtly ]: labels and declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-18 16:03 -0700
Re: [ On topic, amazingtly ]: labels and declarations Bart <bc@freeuk.com> - 2019-03-18 23:49 +0000
Re: [ On topic, amazingtly ]: labels and declarations fir is a sexy shemale <cdalten@gmail.com> - 2019-03-18 16:53 -0700
Re: [ On topic, amazingtly ]: labels and declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-18 18:03 -0700
Re: [ On topic, amazingtly ]: labels and declarations David Brown <david.brown@hesbynett.no> - 2019-03-18 13:16 +0100
Re: [ On topic, amazingtly ]: labels and declarations Bart <bc@freeuk.com> - 2019-03-18 12:30 +0000
Re: [ On topic, amazingtly ]: labels and declarations David Brown <david.brown@hesbynett.no> - 2019-03-18 13:41 +0100
Re: [ On topic, amazingtly ]: labels and declarations fir <profesor.fir@gmail.com> - 2019-03-18 06:54 -0700
Re: [ On topic, amazingtly ]: labels and declarations fir <profesor.fir@gmail.com> - 2019-03-18 07:05 -0700
Re: [ On topic, amazingtly ]: labels and declarations fir <profesor.fir@gmail.com> - 2019-03-18 09:07 -0700
Re: [ On topic, amazingtly ]: labels and declarations Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-03-18 06:46 -0700
Re: [ On topic, amazingtly ]: labels and declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-18 07:25 -0700
Re: [ On topic, amazingtly ]: labels and declarations Manfred <noname@add.invalid> - 2019-03-21 17:48 +0100
Re: [ On topic, amazingtly ]: labels and declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-21 10:04 -0700
Re: [ On topic, amazingtly ]: labels and declarations fir is a sexy shemale <cdalten@gmail.com> - 2019-03-21 10:34 -0700
Re: [ On topic, amazingtly ]: labels and declarations Jorgen Grahn <grahn+nntp@snipabacken.se> - 2019-03-21 20:19 +0000
Re: [ On topic, amazingtly ]: labels and declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-21 14:29 -0700
Re: [ On topic, amazingtly ]: labels and declarations Chad <cdalten@gmail.com> - 2019-03-22 10:15 -0700
Re: [ On topic, amazingtly ]: labels and declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-22 13:58 -0700
Re: [ On topic, amazingtly ]: labels and declarations Chad <cdalten@gmail.com> - 2019-03-22 15:10 -0700
Re: [ On topic, amazingtly ]: labels and declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-22 15:31 -0700
Re: [ On topic, amazingtly ]: labels and declarations David Brown <david.brown@hesbynett.no> - 2019-03-22 09:22 +0100
Re: [ On topic, amazingtly ]: labels and declarations Chad <cdalten@gmail.com> - 2019-03-22 09:28 -0700
Re: [ On topic, amazingtly ]: labels and declarations Manfred <invalid@add.invalid> - 2019-03-22 18:15 +0100
Re: [ On topic, amazingtly ]: labels and declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-22 10:51 -0700
Re: [ On topic, amazingtly ]: labels and declarations Keith Thompson <kst-u@mib.org> - 2019-03-22 11:31 -0700
Re: [ On topic, amazingtly ]: labels and declarations Manfred <noname@add.invalid> - 2019-03-23 17:43 +0100
Re: [ On topic, amazingtly ]: labels and declarations Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-03-23 13:36 -0700
Re: [ On topic, amazingtly ]: labels and declarations Richard Damon <Richard@Damon-Family.org> - 2019-03-23 17:37 -0400
Re: [ On topic, amazingtly ]: labels and declarations Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-03-25 09:18 -0700
Re: [ On topic, amazingtly ]: labels and declarations James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-03-22 12:59 -0700
Re: [ On topic, amazingtly ]: labels and declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-22 14:03 -0700
Re: [ On topic, amazingtly ]: labels and declarations David Brown <david.brown@hesbynett.no> - 2019-03-23 12:44 +0100
Re: [ On topic, amazingtly ]: labels and declarations Robert Wessel <robertwessel2@yahoo.com> - 2019-03-24 10:10 -0500
Re: [ On topic, amazingtly ]: labels and declarations Manfred <noname@add.invalid> - 2019-03-23 17:48 +0100
Re: [ On topic, amazingtly ]: labels and declarations James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-03-25 11:32 -0700
Re: [ On topic, amazingtly ]: labels and declarations Robert Wessel <robertwessel2@yahoo.com> - 2019-03-21 22:22 -0500
Re: [ On topic, amazingtly ]: labels and declarations Manfred <noname@add.invalid> - 2019-03-22 17:45 +0100
Re: [ On topic, amazingtly ]: labels and declarations Keith Thompson <kst-u@mib.org> - 2019-03-22 11:13 -0700
Re: [ On topic, amazingtly ]: labels and declarations Manfred <noname@add.invalid> - 2019-03-23 18:20 +0100
Re: [ On topic, amazingtly ]: labels and declarations Keith Thompson <kst-u@mib.org> - 2019-03-23 11:57 -0700
Re: [ On topic, amazingtly ]: labels and declarations James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-03-25 10:58 -0700
Re: [ On topic, amazingtly ]: labels and declarations Keith Thompson <kst-u@mib.org> - 2019-03-25 13:17 -0700
Re: [ On topic, amazingtly ]: labels and declarations Keith Thompson <kst-u@mib.org> - 2019-03-17 16:16 -0700
Re: [ On topic, amazingtly ]: labels and declarations Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2019-03-17 19:29 -0400
Re: [ On topic, amazingtly ]: labels and declarations Keith Thompson <kst-u@mib.org> - 2019-03-17 16:49 -0700
Re: [ On topic, amazingtly ]: labels and declarations Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2019-03-17 19:51 -0400
Re: [ On topic, amazingtly ]: labels and declarations Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-03-17 17:41 -0700
Re: [ On topic, amazingtly ]: labels and declarations Richard Damon <Richard@Damon-Family.org> - 2019-03-17 22:53 -0400
Re: [ On topic, amazingtly ]: labels and declarations Keith Thompson <kst-u@mib.org> - 2019-03-17 21:08 -0700
Re: [ On topic, amazingtly ]: labels and declarations Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-03-17 21:40 -0700
Re: [ On topic, amazingtly ]: labels and declarations gazelle@shell.xmission.com (Kenny McCormack) - 2019-03-18 05:03 +0000
Re: [ On topic, amazingtly ]: labels and declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-18 02:30 -0700
Re: [ On topic, amazingtly ]: labels and declarations Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-03-18 06:32 -0700
Re: [ On topic, amazingtly ]: labels and declarations gazelle@shell.xmission.com (Kenny McCormack) - 2019-03-18 16:06 +0000
Re: [ On topic, amazingtly ]: labels and declarations Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-03-17 22:19 -0700
Re: [ On topic, amazingtly ]: labels and declarations Richard Damon <Richard@Damon-Family.org> - 2019-03-17 20:07 -0400
Re: [ On topic, amazingtly ]: labels and declarations luser droog <luser.droog@gmail.com> - 2019-03-17 12:37 -0700
Re: [ On topic, amazingtly ]: labels and declarations "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2019-03-18 11:00 +0800
Re: [ On topic, amazingtly ]: labels and declarations "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2019-03-18 22:43 +0800
Re: [ On topic, amazingtly ]: labels and declarations "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-18 08:00 -0700
Re: [ On topic, amazingtly ]: labels and declarations "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2019-03-19 13:11 +0800
Telling Fred where to go... (Was: [ On topic, amazingtly ]: labels and declarations) gazelle@shell.xmission.com (Kenny McCormack) - 2019-03-19 05:27 +0000
Re: Telling Fred where to go... (Was: [ On topic, amazingtly ]: labels and declarations) "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2019-03-19 14:40 +0800
Re: Telling Fred where to go... (Was: [ On topic, amazingtly ]: labels and declarations) "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-19 04:39 -0700
Re: Telling Fred where to go... (Was: [ On topic, amazingtly ]: labels and declarations) "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2019-03-19 19:44 +0800
Re: Telling Fred where to go... (Was: [ On topic, amazingtly ]: labels and declarations) fir is a sexy shemale <cdalten@gmail.com> - 2019-03-19 05:11 -0700
Re: Use of goto in high-level C programming "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2019-03-19 20:13 +0800
Re: Use of goto in high-level C programming fir is a sexy shemale <cdalten@gmail.com> - 2019-03-19 05:42 -0700
Re: Use of goto in high-level C programming "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2019-03-19 20:44 +0800
Re: Use of goto in high-level C programming Wouter Verhelst <w@uter.be> - 2019-03-20 08:16 +0200
Re: Use of goto in high-level C programming "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2019-03-20 19:16 +0800
Re: Telling Fred where to go... (Was: [ On topic, amazingtly ]: labels and declarations) fir is a sexy shemale <cdalten@gmail.com> - 2019-03-19 05:13 -0700
Re: Telling Fred where to go... (Was: [ On topic, amazingtly ]: labels and declarations) "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-19 05:56 -0700
Re: Telling Fred where to go... (Was: [ On topic, amazingtly ]: labels and declarations) fir is a sexy shemale <cdalten@gmail.com> - 2019-03-19 06:30 -0700
Re: Telling Fred where to go... (Was: [ On topic, amazingtly ]: labels and declarations) "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-19 06:54 -0700
Re: Telling Fred where to go... (Was: [ On topic, amazingtly ]: labels and declarations) fir is a sexy shemale <cdalten@gmail.com> - 2019-03-19 07:12 -0700
Re: Telling Fred where to go... (Was: [ On topic, amazingtly ]: labels and declarations) "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-03-19 12:03 -0700
Re: Telling Fred where to go... (Was: [ On topic, amazingtly ]: labels and declarations) fir is a sexy shemale <cdalten@gmail.com> - 2019-03-19 13:33 -0700
Re: [ On topic, amazingtly ]: labels and declarations fir is a sexy shemale <cdalten@gmail.com> - 2019-03-19 05:17 -0700
Re: from programming to religion and then.... sex? "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2019-03-19 20:23 +0800
Re: from programming to religion and then.... sex? fir is a sexy shemale <cdalten@gmail.com> - 2019-03-19 05:40 -0700
Re: from programming to religion and then.... sex? "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2019-03-19 20:46 +0800
Re: from programming to religion and then.... sex? fir is a sexy shemale <cdalten@gmail.com> - 2019-03-19 06:30 -0700
Re: from programming to religion and then.... sex? "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2019-03-19 21:36 +0800
Re: from programming to religion and then.... sex? fir is a sexy shemale <cdalten@gmail.com> - 2019-03-19 07:08 -0700
Re: from programming to religion and then.... sex? "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2019-03-20 19:16 +0800
Re: [ On topic, amazingtly ]: labels and declarations John Bode <jfbode1029@gmail.com> - 2019-03-19 14:58 -0700
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