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| Message-ID | <4ED971FE.7646@mindspring.com> (permalink) |
|---|---|
| Date | 2011-12-02 19:49 -0500 |
| From | pete <pfiland@mindspring.com> |
| Organization | PF |
| Newsgroups | comp.lang.c |
| Subject | Re: casting constant value from float to unsigned short - compiler bugs? |
| References | <4ed8950a$0$18699$91cee783@newsreader03.highway.telekom.at> <jba62t$41l$1@speranza.aioe.org> <jbbjsk$ja4$2@speranza.aioe.org> <jbbnue$sau$1@speranza.aioe.org> <4ED970C8.1F03@mindspring.com> |
pete wrote:
>
> jacob navia wrote:
> >
> > Le 02/12/11 23:36, Quentin Pope a écrit :
> > > On Fri, 02 Dec 2011 10:34:22 +0100, jacob navia wrote:
> > >> Yes. The first one is that the range for unsigned short is zero to
> > >> USHORT_MAX. Your program has undefined behavior
> > >> since a negative value
> > >> will not go into an unsigned short, it is OUTSIDE its domain.
> > >
> > > Sorry, but this is nonsense.
> > > Negative numbers stored in unsigned integer
> > > types "wrap around" - there is NO overflow for unsigned types,
> > > but all arithmetic is done modulo USHORT_MAX+1.
> > > It is amazing that you are not
> > > aware of this as a compiler writer!
> >
> > The C standard specifies that when the
> >
> > <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.
> >
> > By definition.
>
> You got that all wrong.
Sorry about that.
I got that all wrong.
I hadn't read back far enough into thread
to realise what you were talking about.
6.3.1.4 Real floating and integer
1 When a finite value of real floating type
is converted to an integer type other than _Bool,
the fractional part is discarded
(i.e., the value is truncated toward zero).
If the value of the integral part
cannot be represented by the integer type,
the behavior is undefined.)
--
pete
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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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