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| From | Jens Gustedt <jens.gustedt@loria.fr> |
|---|---|
| Newsgroups | comp.std.c |
| Subject | Re: Initial draft proposal: "Safe arrays and pointers for C" |
| Date | 2012-08-15 08:47 +0200 |
| Organization | A noiseless patient Spider |
| Message-ID | <502B45FC.8030007@loria.fr> (permalink) |
| References | (3 earlier) <lnr4rarqqz.fsf@nuthaus.mib.org> <k0e4tl$892$1@dont-email.me> <lnipclrv6q.fsf@nuthaus.mib.org> <k0ejr1$6gj$1@dont-email.me> <502AD810.4000601@verizon.net> |
Am 15.08.2012 00:58, schrieb James Kuyper: > On 08/14/2012 06:35 PM, John Nagle wrote: >> What's the use case for that, anyway? > > It's nothing more or less than an alternative way of saying "double > *const arr" in a function parameter declaration. Arguably, we don't need > another way of saying "double *const arr", but that same argument > applies to using "double arr[100]" as an alternative way of saying > "double *arr". Declaring a pointer as if it were an array remains > popular, and as long as that's the case, providing a way to insert a > qualifier so that it applies to the pointer itself, rather than the > thing it points at, makes that alternative a little more convenient. This feature was introduced with the [static ] concept in this context. double a[static 100] is a declaration of a pointer parameter double * a that in addition has the sematic to point to an array object of at least 100 elements. This is not expressible with a double * a interface specification, alone. Now if you have that you also want the possibility to express the property that the pointer (itself) is qualified. Thus double a[static const 100] is equivalent with an interface having double *const a and the additional constraint on the size of the object that is pointed to. As the discussion here proves this feature is not well known, and most compilers just implement it by silently ignoring the "static". So we have an interface that could be used to do at least a rudimentary bound checking, but nobody uses it. My guess would be that checking this with non-VLA should be easy at compile time since the expression that is allowed (here the "100") must be a constant integer expression. To my knowledge nobody does that yet, but it would be a good point to start. (We have a compiler writer participating in this discussion, so go ahead give it a try.) Checking this with a VLA that is passed as a parameter would be a runtime check, so it probably needs a bit more effort to implement. But the "bounds checking interfaces" could probably be a starting point of doing these things. Jens
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Initial draft proposal: "Safe arrays and pointers for C" John Nagle <nagle@animats.com> - 2012-08-13 11:39 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" Jens Gustedt <jens.gustedt@loria.fr> - 2012-08-13 23:23 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" Keith Thompson <kst-u@mib.org> - 2012-08-13 17:04 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" John Nagle <nagle@animats.com> - 2012-08-13 20:08 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" Keith Thompson <kst-u@mib.org> - 2012-08-13 22:23 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" John Nagle <nagle@animats.com> - 2012-08-14 11:20 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" James Kuyper <jameskuyper@verizon.net> - 2012-08-14 14:54 -0400
Re: Initial draft proposal: "Safe arrays and pointers for C" Jens Gustedt <jens.gustedt@loria.fr> - 2012-08-14 21:09 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" James Kuyper <jameskuyper@verizon.net> - 2012-08-14 16:00 -0400
Re: Initial draft proposal: "Safe arrays and pointers for C" James Kuyper <jameskuyper@verizon.net> - 2012-08-14 18:08 -0400
Re: Initial draft proposal: "Safe arrays and pointers for C" Philip Lantz <prl@canterey.us> - 2012-08-14 23:05 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" James Kuyper <jameskuyper@verizon.net> - 2012-08-15 06:48 -0400
Re: Initial draft proposal: "Safe arrays and pointers for C" John Nagle <nagle@animats.com> - 2012-08-15 11:22 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" James Kuyper <jameskuyper@verizon.net> - 2012-08-15 15:13 -0400
Re: Initial draft proposal: "Safe arrays and pointers for C" John Nagle <nagle@animats.com> - 2012-08-15 13:00 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2012-08-15 22:52 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" James Kuyper <jameskuyper@verizon.net> - 2012-08-15 17:18 -0400
Re: Initial draft proposal: "Safe arrays and pointers for C" Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2012-08-16 19:20 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" James Kuyper <jameskuyper@verizon.net> - 2012-08-16 13:40 -0400
Re: Initial draft proposal: "Safe arrays and pointers for C" Keith Thompson <kst-u@mib.org> - 2012-08-16 11:04 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" James Kuyper <jameskuyper@verizon.net> - 2012-08-16 14:35 -0400
Re: Initial draft proposal: "Safe arrays and pointers for C" Keith Thompson <kst-u@mib.org> - 2012-08-16 11:47 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" James Kuyper <jameskuyper@verizon.net> - 2012-08-16 14:52 -0400
Re: Initial draft proposal: "Safe arrays and pointers for C" Keith Thompson <kst-u@mib.org> - 2012-08-15 14:41 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" "Derek M. Jones" <derek@_NOSPAM_knosof.co.uk> - 2012-08-16 12:39 +0100
Re: Initial draft proposal: "Safe arrays and pointers for C" John Nagle <nagle@animats.com> - 2012-08-16 09:57 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" James Kuyper <jameskuyper@verizon.net> - 2012-08-16 13:28 -0400
Re: Initial draft proposal: "Safe arrays and pointers for C" "Derek M. Jones" <derek@_NOSPAM_knosof.co.uk> - 2012-08-16 23:52 +0100
Re: Initial draft proposal: "Safe arrays and pointers for C" Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2012-08-15 18:56 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" jacob navia <jacob@spamsink.net> - 2012-08-15 19:23 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" Philip Lantz <prl@canterey.us> - 2012-08-15 21:47 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2012-08-16 19:14 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" Jens Gustedt <jens.gustedt@loria.fr> - 2012-08-16 20:28 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" James Kuyper <jameskuyper@verizon.net> - 2012-08-14 15:05 -0400
Re: Initial draft proposal: "Safe arrays and pointers for C" Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2012-08-14 21:09 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" John Nagle <nagle@animats.com> - 2012-08-14 13:24 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" James Kuyper <jameskuyper@verizon.net> - 2012-08-14 16:39 -0400
Re: Initial draft proposal: "Safe arrays and pointers for C" Keith Thompson <kst-u@mib.org> - 2012-08-14 15:23 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" Philip Lantz <prl@canterey.us> - 2012-08-14 22:58 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2012-08-15 00:37 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" Keith Thompson <kst-u@mib.org> - 2012-08-14 16:42 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2012-08-15 22:57 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" Keith Thompson <kst-u@mib.org> - 2012-08-15 17:02 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" Keith Thompson <kst-u@mib.org> - 2012-08-14 14:59 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" John Nagle <nagle@animats.com> - 2012-08-14 15:35 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" Jens Gustedt <jens.gustedt@loria.fr> - 2012-08-15 00:51 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" jacob navia <jacob@spamsink.net> - 2012-08-15 06:43 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" Jens Gustedt <jens.gustedt@loria.fr> - 2012-08-15 08:31 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" jacob navia <jacob@spamsink.net> - 2012-08-15 09:14 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" James Kuyper <jameskuyper@verizon.net> - 2012-08-14 18:58 -0400
Re: Initial draft proposal: "Safe arrays and pointers for C" jacob navia <jacob@spamsink.net> - 2012-08-15 06:45 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" Philip Lantz <prl@canterey.us> - 2012-08-14 22:51 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" James Kuyper <jameskuyper@verizon.net> - 2012-08-15 07:18 -0400
Re: Initial draft proposal: "Safe arrays and pointers for C" Jens Gustedt <jens.gustedt@loria.fr> - 2012-08-15 14:15 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" jacob navia <jacob@spamsink.net> - 2012-08-15 14:28 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" Jens Gustedt <jens.gustedt@loria.fr> - 2012-08-15 14:36 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" jacob navia <jacob@spamsink.net> - 2012-08-15 14:54 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" Jens Gustedt <jens.gustedt@loria.fr> - 2012-08-15 15:08 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" Keith Thompson <kst-u@mib.org> - 2012-08-15 12:50 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" Jens Gustedt <jens.gustedt@loria.fr> - 2012-08-15 23:22 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" John Nagle <nagle@animats.com> - 2012-08-15 14:38 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" Jens Gustedt <jens.gustedt@loria.fr> - 2012-08-16 00:51 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" John Nagle <nagle@animats.com> - 2012-08-15 16:32 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" Jens Gustedt <jens.gustedt@loria.fr> - 2012-08-16 09:05 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" Keith Thompson <kst-u@mib.org> - 2012-08-15 17:22 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" John Nagle <nagle@animats.com> - 2012-08-15 20:29 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" Keith Thompson <kst-u@mib.org> - 2012-08-15 12:36 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" James Kuyper <jameskuyper@verizon.net> - 2012-08-15 16:09 -0400
Re: Initial draft proposal: "Safe arrays and pointers for C" Jens Gustedt <jens.gustedt@loria.fr> - 2012-08-15 08:47 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" Keith Thompson <kst-u@mib.org> - 2012-08-14 16:33 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" Keith Thompson <kst-u@mib.org> - 2012-08-14 16:38 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" jacob navia <jacob@spamsink.net> - 2012-08-15 06:46 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" Keith Thompson <kst-u@mib.org> - 2012-08-14 22:28 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" Jens Gustedt <jens.gustedt@loria.fr> - 2012-08-15 08:34 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" jacob navia <jacob@spamsink.net> - 2012-08-15 09:12 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" John Nagle <nagle@animats.com> - 2012-08-16 13:09 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" Wojtek Lerch <wojtek_l@yahoo.ca> - 2012-08-16 16:21 -0400
Re: Initial draft proposal: "Safe arrays and pointers for C" John Nagle <nagle@animats.com> - 2012-08-16 14:22 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" Keith Thompson <kst-u@mib.org> - 2012-08-16 15:28 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" Wojtek Lerch <wojtek_l@yahoo.ca> - 2012-08-16 19:49 -0400
Re: Initial draft proposal: "Safe arrays and pointers for C" Jens Gustedt <jens.gustedt@loria.fr> - 2012-08-14 08:56 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" James Kuyper <jameskuyper@verizon.net> - 2012-08-14 06:18 -0400
Re: Initial draft proposal: "Safe arrays and pointers for C" Jens Gustedt <jens.gustedt@loria.fr> - 2012-08-14 12:42 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" John Nagle <nagle@animats.com> - 2012-08-14 09:43 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2012-08-14 19:52 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" jacob navia <jacob@spamsink.net> - 2012-08-14 21:03 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" Jens Gustedt <jens.gustedt@loria.fr> - 2012-08-14 21:39 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-08-14 08:26 -0400
Re: Initial draft proposal: "Safe arrays and pointers for C" Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-08-13 22:44 +0100
Re: Initial draft proposal: "Safe arrays and pointers for C" John Nagle <nagle@animats.com> - 2012-08-13 18:05 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" jacob navia <jacob@spamsink.net> - 2012-08-14 21:00 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" Marc <marc.glisse@gmail.com> - 2012-08-14 21:18 +0000
Re: Initial draft proposal: "Safe arrays and pointers for C" jacob navia <jacob@spamsink.net> - 2012-08-14 23:51 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" John Nagle <nagle@animats.com> - 2012-08-17 09:40 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" Jens Gustedt <jens.gustedt@loria.fr> - 2012-08-17 21:00 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" John Nagle <nagle@animats.com> - 2012-08-17 13:30 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" jacob navia <jacob@spamsink.net> - 2012-08-17 23:14 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" Jens Gustedt <jens.gustedt@loria.fr> - 2012-08-18 01:07 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" John Nagle <nagle@animats.com> - 2012-08-19 23:14 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" Ike Naar <ike@sverige.freeshell.org> - 2012-08-20 07:16 +0000
Re: Initial draft proposal: "Safe arrays and pointers for C" John Nagle <nagle@animats.com> - 2012-08-20 00:25 -0700
Re: Initial draft proposal: "Safe arrays and pointers for C" Jens Gustedt <jens.gustedt@loria.fr> - 2012-08-20 11:49 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2012-08-20 22:40 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" jacob navia <jacob@spamsink.net> - 2012-08-20 23:08 +0200
Re: Initial draft proposal: "Safe arrays and pointers for C" Keith Thompson <kst-u@mib.org> - 2012-08-17 15:33 -0700
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