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| From | Quentin Pope <qp19433@hotmail.NOSPAM.com> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: casting constant value from float to unsigned short - compiler bugs? |
| Date | 2011-12-03 19:06 +0000 |
| Organization | Aioe.org NNTP Server |
| Message-ID | <jbdruv$90g$1@speranza.aioe.org> (permalink) |
| References | (2 earlier) <jbbjsk$ja4$2@speranza.aioe.org> <jbbnue$sau$1@speranza.aioe.org> <squdnRldpaA_70TTnZ2dnUVZ8radnZ2d@giganews.com> <jbdk1p$pgh$1@dont-email.me> <IcOdneGVp6Y3-EfTnZ2dnUVZ8k6dnZ2d@giganews.com> |
On Sat, 03 Dec 2011 19:08:42 +0100, Vincenzo Mercuri wrote: > Il 03/12/2011 17:51, James Kuyper ha scritto: >> On 12/02/2011 07:51 PM, Vincenzo Mercuri wrote: > ... >>> But now we are dealing with a real floating type being converted to >>> integer types, not the contrary! >> >> His conclusion was correct, and he cited the right section of the >> standard, but his quotation is from the wrong paragraph in that >> section. What he should have cited was 6.3.1.4p1, which does cover >> conversion of a real floating type to an integer: "If the value of the >> integral part cannot be represented by the integer type, the behavior >> is undefined." > > Yes, of course. That's what I wanted to point out indeed: the right > context in the Standard. I do believe that Jacob intended the right > thing, but he expressed it in the form of a very general rule about > conversion from "negative value"s to unsigned types that will eventually > lead to undefined behavior. He said: > > "Your program has undefined behavior since a negative value will not go > into an unsigned short, it is OUTSIDE its domain. " > > and > > "<quote> (C Standard 6.3.1.4) > If the value being converted is outside the range of values that can > be represented, the behavior is undefined. > <end quote> > > A negative value can't be represented in an UNsigned integer. " > > One who didn't read the Standard might have been convinced of the > general rule for which a conversion of *any* type of negative value to > an unsigned type invokes UB. This is not true (even if the context looks > clear to most, but it may not be so to everyone). This is the reason of > my replies. :) Yes! This is exactly the point I was making. The clear implication of Jacob's words is that he was referring generally to all conversions of numeric types to unsigned short, not just to floating point types.
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casting constant value from float to unsigned short - compiler bugs? "news.aon.at" <mario_semo@hotmail.com> - 2011-12-02 10:06 +0100
Re: casting constant value from float to unsigned short - compiler bugs? jacob navia <jacob@spamsink.net> - 2011-12-02 10:34 +0100
Re: casting constant value from float to unsigned short - compiler bugs? Vincenzo Mercuri <vincenzo.mercuri@hotmail.it> - 2011-12-02 18:10 +0100
Re: casting constant value from float to unsigned short - compiler bugs? Quentin Pope <qp19433@hotmail.NOSPAM.com> - 2011-12-02 22:36 +0000
Re: casting constant value from float to unsigned short - compiler bugs? jacob navia <jacob@spamsink.net> - 2011-12-03 00:45 +0100
Re: casting constant value from float to unsigned short - compiler bugs? pete <pfiland@mindspring.com> - 2011-12-02 19:43 -0500
Re: casting constant value from float to unsigned short - compiler bugs? pete <pfiland@mindspring.com> - 2011-12-02 19:49 -0500
Re: casting constant value from float to unsigned short - compiler bugs? Vincenzo Mercuri <vincenzo.mercuri@yahoo.it> - 2011-12-03 01:51 +0100
Re: casting constant value from float to unsigned short - compiler bugs? James Kuyper <jameskuyper@verizon.net> - 2011-12-03 11:51 -0500
Re: casting constant value from float to unsigned short - compiler bugs? Vincenzo Mercuri <vincenzo.mercuri@hotmail.it> - 2011-12-03 19:08 +0100
Re: casting constant value from float to unsigned short - compiler bugs? Quentin Pope <qp19433@hotmail.NOSPAM.com> - 2011-12-03 19:06 +0000
Re: casting constant value from float to unsigned short - compiler bugs? Kaz Kylheku <kaz@kylheku.com> - 2011-12-03 19:14 +0000
Re: casting constant value from float to unsigned short - compiler bugs? Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-12-04 17:19 +0200
Re: casting constant value from float to unsigned short - compiler bugs? James Kuyper <jameskuyper@verizon.net> - 2011-12-04 10:39 -0500
Re: casting constant value from float to unsigned short - compiler bugs? Vincenzo Mercuri <vincenzo.mercuri@yahoo.it> - 2011-12-03 01:41 +0100
Re: casting constant value from float to unsigned short - compiler bugs? Michael Press <rubrum@pacbell.net> - 2012-01-03 12:31 -0800
Re: casting constant value from float to unsigned short - compiler bugs? blp@cs.stanford.edu (Ben Pfaff) - 2012-01-03 12:38 -0800
Re: casting constant value from float to unsigned short - compiler bugs? Michael Press <rubrum@pacbell.net> - 2012-01-06 11:38 -0800
Re: casting constant value from float to unsigned short - compiler bugs? James Kuyper <jameskuyper@verizon.net> - 2012-01-06 15:10 -0500
Re: casting constant value from float to unsigned short - compiler bugs? Keith Thompson <kst-u@mib.org> - 2012-01-03 12:49 -0800
Re: casting constant value from float to unsigned short - compiler bugs? Michael Press <rubrum@pacbell.net> - 2012-01-04 15:14 -0800
Re: casting constant value from float to unsigned short - compiler bugs? James Kuyper <jameskuyper@verizon.net> - 2012-01-04 19:12 -0500
Re: casting constant value from float to unsigned short - compiler bugs? Michael Press <rubrum@pacbell.net> - 2012-01-04 23:04 -0800
Re: casting constant value from float to unsigned short - compiler bugs? Keith Thompson <kst-u@mib.org> - 2012-01-05 02:43 -0800
Re: casting constant value from float to unsigned short - compiler bugs? James Kuyper <jameskuyper@verizon.net> - 2012-01-05 07:14 -0500
Re: casting constant value from float to unsigned short - compiler bugs? Michael Press <rubrum@pacbell.net> - 2012-01-06 11:39 -0800
Re: casting constant value from float to unsigned short - compiler bugs? Michael Press <rubrum@pacbell.net> - 2012-01-05 16:14 -0800
Re: casting constant value from float to unsigned short - compiler bugs? Keith Thompson <kst-u@mib.org> - 2012-01-05 16:44 -0800
Re: casting constant value from float to unsigned short - compiler bugs? Michael Press <rubrum@pacbell.net> - 2012-01-06 11:30 -0800
Re: casting constant value from float to unsigned short - compiler bugs? James Kuyper <jameskuyper@verizon.net> - 2012-01-06 15:24 -0500
Re: casting constant value from float to unsigned short - compiler bugs? Tim Rentsch <txr@alumni.caltech.edu> - 2012-01-26 09:14 -0800
Re: casting constant value from float to unsigned short - compiler bugs? gwowen <gwowen@gmail.com> - 2012-01-05 04:09 -0800
Re: casting constant value from float to unsigned short - compiler bugs? "io_x" <a@b.c.invalid> - 2012-01-05 16:32 +0100
Re: casting constant value from float to unsigned short - compiler bugs? Nobody <nobody@nowhere.com> - 2012-01-04 09:11 +0000
Re: casting constant value from float to unsigned short - compiler bugs? Michael Press <rubrum@pacbell.net> - 2012-01-04 23:08 -0800
Re: casting constant value from float to unsigned short - compiler bugs? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-01-05 11:15 +0000
Re: casting constant value from float to unsigned short - compiler bugs? James Kuyper <jameskuyper@verizon.net> - 2012-01-05 07:27 -0500
Re: casting constant value from float to unsigned short - compiler bugs? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-01-05 13:03 +0000
Re: casting constant value from float to unsigned short - compiler bugs? Michael Press <rubrum@pacbell.net> - 2012-01-05 16:28 -0800
Re: casting constant value from float to unsigned short - compiler bugs? James Kuyper <jameskuyper@verizon.net> - 2012-01-06 07:17 -0500
Re: casting constant value from float to unsigned short - compiler bugs? lawrence.jones@siemens.com - 2012-01-06 12:04 -0500
Re: casting constant value from float to unsigned short - compiler bugs? Tim Rentsch <txr@alumni.caltech.edu> - 2012-01-26 09:08 -0800
Re: casting constant value from float to unsigned short - compiler bugs? Michael Press <rubrum@pacbell.net> - 2012-01-05 16:17 -0800
Re: casting constant value from float to unsigned short - compiler bugs? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-12-03 01:50 +0000
Re: casting constant value from float to unsigned short - compiler bugs? James Kuyper <jameskuyper@verizon.net> - 2011-12-02 06:41 -0500
Re: casting constant value from float to unsigned short - compiler bugs? Vincenzo Mercuri <vincenzo.mercuri@hotmail.it> - 2011-12-02 16:26 +0100
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