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| From | Ben Bacarisse <ben.usenet@bsb.me.uk> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: who invented static? |
| Date | 2015-08-30 21:18 +0100 |
| Organization | A noiseless patient Spider |
| Message-ID | <87io7wwmwu.fsf@bsb.me.uk> (permalink) |
| References | (4 earlier) <55E21F50.2080705@verizon.net> <mrv5f3$g9b$1@dont-email.me> <55E32CBB.2050001@verizon.net> <mrvcnh$fju$1@dont-email.me> <m_GEx.8461$1H1.2009@fx23.iad> |
Richard Damon <Richard@Damon-Family.org> writes: > On 8/30/15 1:00 PM, David Brown wrote: >> On 30/08/15 18:18, James Kuyper wrote: >>> On 08/30/2015 10:56 AM, David Brown wrote: >>>> On 29/08/15 23:08, James Kuyper wrote: >>>> >>>>> The following use of "static" is new in C99, and can only occur in the >>>>> leading dimension of a function parameter declared as an array: >>>>> "If the keyword static also appears within the [ and ] of the array >>>>> type >>>>> derivation, then for each call to the function, the value of the >>>>> corresponding actual argument shall provide access to the first element >>>>> of an array with at least as many elements as specified by the size >>>>> expression." 6.7.6.3p7 <snip> >>> Given: >>> >>> void f(int array[static 3]); >>> int large_array[6]; >>> int small_array[2]; >>> int *p = small_array; >>> >>> then f(large_array) is fine, because large_array has more than 3 >>> elements. However, f(small_array) violates a "shall" that occurs outside >>> of a constraint, because small_array has fewer than 3 elements. The >>> behavior is therefore undefined. I would have preferred that this be a >>> constraint violation, and I would expect any decent implementation of >>> C99 or later to issue the diagnostic message that would be mandatory if >>> it were a constraint violation - in my opinion, that possibility is the >>> only thing that makes this feature worthwhile. I think that the reason >>> why it cannot be made a constraint violation is that f(p) is also a >>> violation of the same rule, and unlike f(small_array), it's not in >>> general easy for a compiler to identify the fact that an arbitrary >>> pointer points at location which violates this rule. I think it's simpler to say that it can't be a constraint because it can't be diagnosed. You could come up with some set of rules about what deductions a compiler must use, and then base a rather complex constraint on those but it would be a bit arbitrary. >> But surely if g were defined: >> >> void g(int array[3]); >> >> Then g(small_array) would still be a constraint violation? Or is it >> defined behaviour to call g(small_array), and only becomes undefined if >> g() accesses array[2] ? >> >> It seems to me that even without the "static", g is asking for a >> parameter with particular characteristics, and calling g(small_array) is >> breaking that requirement. > > in c, this definition of g is IDENTICAL to (by a rewrite rule) > void g(int *array); > > (note, the 3 is lost) > Thus, the passing of anything that is an int* or decays to an int* > (like an array of any size of int) is valid. > > Adding the static keyword changes the type of that parameter so that > the compiler actually remembers the needed bounds, and will check that > the passed array is large enough. The compiler can't always do that check but maybe you were talking about the example given. Anyway, where does the idea that static changes the type of the parameter come from? I don't see that at all. <snip> -- Ben.
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who invented static? fir <profesor.fir@gmail.com> - 2015-08-29 11:40 -0700
Re: who invented static? David Kleinecke <dkleinecke@gmail.com> - 2015-08-29 13:36 -0700
Re: who invented static? fir <profesor.fir@gmail.com> - 2015-08-29 13:46 -0700
Re: who invented static? David Kleinecke <dkleinecke@gmail.com> - 2015-08-29 13:53 -0700
Re: who invented static? James Kuyper <jameskuyper@verizon.net> - 2015-08-29 17:08 -0400
Re: who invented static? David Brown <david.brown@hesbynett.no> - 2015-08-30 16:56 +0200
Re: who invented static? James Kuyper <jameskuyper@verizon.net> - 2015-08-30 12:18 -0400
Re: who invented static? David Brown <david.brown@hesbynett.no> - 2015-08-30 19:00 +0200
Re: who invented static? Richard Damon <Richard@Damon-Family.org> - 2015-08-30 13:23 -0400
Re: who invented static? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-08-30 21:18 +0100
Re: who invented static? Tim Rentsch <txr@alumni.caltech.edu> - 2015-09-06 19:33 -0700
Re: who invented static? Tim Rentsch <txr@alumni.caltech.edu> - 2015-09-06 19:26 -0700
Re: who invented static? James Kuyper <jameskuyper@verizon.net> - 2015-08-30 13:40 -0400
Re: who invented static? supercat@casperkitty.com - 2015-08-31 06:47 -0700
Re: who invented static? Tim Rentsch <txr@alumni.caltech.edu> - 2015-09-06 19:20 -0700
Re: who invented static? Tim Rentsch <txr@alumni.caltech.edu> - 2015-09-06 18:59 -0700
Re: who invented static? David Brown <david.brown@hesbynett.no> - 2015-09-07 10:25 +0200
Re: who invented static? Keith Thompson <kst-u@mib.org> - 2015-09-07 01:59 -0700
Re: who invented static? David Brown <david.brown@hesbynett.no> - 2015-09-07 12:22 +0200
Re: who invented static? James Kuyper <jameskuyper@verizon.net> - 2015-09-07 13:04 -0400
Re: who invented static? David Brown <david.brown@hesbynett.no> - 2015-09-07 21:25 +0200
Re: who invented static? James Kuyper <jameskuyper@verizon.net> - 2015-09-07 15:47 -0400
Re: who invented static? Philip Lantz <prl@canterey.us> - 2015-09-07 13:27 -0700
Re: who invented static? James Kuyper <jameskuyper@verizon.net> - 2015-09-07 17:31 -0400
Re: who invented static? David Brown <david.brown@hesbynett.no> - 2015-09-08 09:16 +0200
Re: who invented static? Keith Thompson <kst-u@mib.org> - 2015-09-07 13:27 -0700
Re: who invented static? David Brown <david.brown@hesbynett.no> - 2015-09-08 09:12 +0200
Re: who invented static? Tim Rentsch <txr@alumni.caltech.edu> - 2015-09-07 16:06 -0700
Re: who invented static? David Brown <david.brown@hesbynett.no> - 2015-09-08 09:08 +0200
Re: who invented static? Keith Thompson <kst-u@mib.org> - 2015-09-08 10:18 -0700
Re: who invented static? James Kuyper <jameskuyper@verizon.net> - 2015-09-08 13:28 -0400
Re: who invented static? fir <profesor.fir@gmail.com> - 2015-08-29 14:18 -0700
Re: who invented static? fir <profesor.fir@gmail.com> - 2015-09-01 01:36 -0700
Re: who invented static? Keith Thompson <kst-u@mib.org> - 2015-08-29 14:27 -0700
Re: who invented static? Siri Cruz <chine.bleu@yahoo.com> - 2015-08-29 14:32 -0700
Re: who invented static? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-08-29 23:03 +0000
Re: who invented static? fir <profesor.fir@gmail.com> - 2015-09-01 01:52 -0700
Re: who invented static? Robert Wessel <robertwessel2@yahoo.com> - 2015-09-01 23:42 -0500
Re: who invented static? fir <profesor.fir@gmail.com> - 2015-09-02 00:14 -0700
Re: who invented static? Richard Heathfield <rjh@cpax.org.uk> - 2015-09-02 08:24 +0100
Re: who invented static? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-09-04 04:25 +0000
Re: who invented static? fir <profesor.fir@gmail.com> - 2015-09-04 00:45 -0700
Re: who invented static? Robert Wessel <robertwessel2@yahoo.com> - 2015-09-04 04:09 -0500
Re: who invented static? fir <profesor.fir@gmail.com> - 2015-09-04 02:35 -0700
Re: who invented static? Robert Wessel <robertwessel2@yahoo.com> - 2015-09-04 23:58 -0500
Re: who invented static? fir <profesor.fir@gmail.com> - 2015-09-05 03:02 -0700
Re: who invented static? wssimms@gmail.com - 2015-09-05 13:14 -0700
Re: who invented static? fir <profesor.fir@gmail.com> - 2015-09-05 13:49 -0700
Re: who invented static? Siri Cruz <chine.bleu@yahoo.com> - 2015-09-05 14:09 -0700
Re: who invented static? gazelle@shell.xmission.com (Kenny McCormack) - 2015-09-05 22:30 +0000
Re: who invented static? wssimms@gmail.com - 2015-09-05 20:41 -0700
Re: who invented static? gazelle@shell.xmission.com (Kenny McCormack) - 2015-09-06 05:28 +0000
Re: who invented static? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-09-05 22:40 -0700
Re: who invented static? James Kuyper <jameskuyper@verizon.net> - 2015-09-06 11:42 -0400
Re: who invented static? Robert Wessel <robertwessel2@yahoo.com> - 2015-09-05 23:38 -0500
Re: who invented static? Siri Cruz <chine.bleu@yahoo.com> - 2015-09-04 02:34 -0700
Re: who invented static? fir <profesor.fir@gmail.com> - 2015-09-04 02:43 -0700
Re: who invented static? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-09-05 01:30 +0000
Re: who invented static? Siri Cruz <chine.bleu@yahoo.com> - 2015-09-04 20:52 -0700
Re: who invented static? Robert Wessel <robertwessel2@yahoo.com> - 2015-09-05 00:03 -0500
Re: who invented static? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-09-05 09:04 +0000
Re: who invented static? fir <profesor.fir@gmail.com> - 2015-09-05 03:02 -0700
Re: who invented static? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-09-05 04:33 -0700
Re: who invented static? Reinhardt Behm <rbehm@hushmail.com> - 2015-09-05 20:08 +0800
Re: who invented static? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-09-05 05:21 -0700
Re: who invented static? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-09-05 06:37 -0700
Re: who invented static? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-09-05 16:54 +0000
Re: who invented static? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-09-05 11:06 +0100
Re: who invented static? fir <profesor.fir@gmail.com> - 2015-09-05 03:17 -0700
Re: who invented static? raltbos@xs4all.nl (Richard Bos) - 2015-09-05 19:14 +0000
Re: who invented static? fir <profesor.fir@gmail.com> - 2015-09-05 12:59 -0700
Re: who invented static? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-09-05 01:24 +0000
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