From: Ian Lance Taylor <ian@wasabisystems.com>
To: Christian Groessler <cpg@aladdin.de>
Cc: GCC List <gcc@gcc.gnu.org>
Subject: Re: signed/unsigned right shift
Date: Mon, 15 Mar 2004 22:17:00 -0000 [thread overview]
Message-ID: <m34qspg3hk.fsf@gossamer.airs.com> (raw)
In-Reply-To: <87ish53h24.fsf@aladdin.de>
Christian Groessler <cpg@aladdin.de> writes:
> Sentence 2 says "If an int can represent all values of the original
> type, the value is converted to an int; otherwise, it is converted to
> an unsigned int."
>
> Seems to suggest that the conversion "unsigned short" to "signed int"
> is ok.
>
> But sentence 3 says "The integer promotions preserve value including
> sign."
>
> So shouldn't the conversion be "unsigned short" to "unsigned int"?
Sentence 3 means that both the value and the sign of the value (i.e.,
positive or negative) are preserved.
Your suggestion would be expressed as "The integer promotions preserve
value including signedness."
K&R C was signedness preserving. ISO C is value preserving. A quick
Google search turned up this page on the topic:
http://ou800doc.caldera.com/SDK_cprog/_Background.html
Ian
next prev parent reply other threads:[~2004-03-15 22:17 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-03-15 22:02 Christian Groessler
2004-03-15 22:14 ` Andreas Schwab
2004-03-15 22:18 ` Andreas Schwab
2004-03-15 22:17 ` Ian Lance Taylor [this message]
-- strict thread matches above, loose matches on Subject: below --
2004-03-15 22:24 Christian Groessler
2004-03-14 18:09 Christian Groessler
2004-03-14 18:23 ` Ian Lance Taylor
2004-03-12 21:25 Christian Groessler
2004-03-12 22:24 ` Andreas Schwab
2004-03-12 22:37 ` Dale Johannesen
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