From: Mark Mitchell <mark@codesourcery.com>
To: Chris Lattner <sabre@nondot.org>, "gcc@gcc.gnu.org" <gcc@gcc.gnu.org>
Subject: RE: pure and const functions
Date: Fri, 26 Apr 2002 12:11:00 -0000 [thread overview]
Message-ID: <169790000.1019847451@gandalf.codesourcery.com> (raw)
In-Reply-To: <Pine.LNX.4.30.0204261145220.2837-100000@nondot.org>
--On Friday, April 26, 2002 11:50:07 AM -0500 Chris Lattner
<sabre@nondot.org> wrote:
>
>> int fib(int n) {
>> if (n==0 || n==1) return n;
>> return fib(n-1) + fib(n-2);
>> }
>
>> According to the definitions given above, this function is const,
>> but not total, because it does not return for negative n.
>
> While this is true in a practical sense, given infinite resources, this is
> certainly not the case. Assuming you had a whole lot of stack space and
> bunch of time, the negative values for 'n' would wrap around to positive
> values. Eventually it would get to 1 and terminate.
Actually, C does not guarantee that negative values wrap around to
positive values.
--
Mark Mitchell mark@codesourcery.com
CodeSourcery, LLC http://www.codesourcery.com
next prev parent reply other threads:[~2002-04-26 19:00 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-04-26 10:17 Chris Lattner
2002-04-26 10:21 ` Kris Warkentin
2002-04-26 10:30 ` Chris Lattner
2002-04-26 10:34 ` Magnus Fromreide
2002-04-26 10:35 ` Chris Lattner
2002-04-26 10:59 ` Magnus Fromreide
2002-04-26 11:03 ` Chris Lattner
2002-04-26 11:27 ` Magnus Fromreide
2002-04-26 12:49 ` Russ Allbery
2002-04-26 10:36 ` Kris Warkentin
2002-04-26 10:46 ` Chris Lattner
2002-04-26 10:26 ` Tim Hollebeek
2002-04-26 10:30 ` Chris Lattner
2002-04-26 10:56 ` Zack Weinberg
2002-04-26 11:01 ` Chris Lattner
2002-08-30 23:02 ` Zack Weinberg
2002-04-26 10:56 ` Tony Finch
2002-04-26 12:11 ` Mark Mitchell [this message]
-- strict thread matches above, loose matches on Subject: below --
2002-04-29 17:25 John Wehle
2002-04-29 9:29 Robert Dewar
2002-04-29 9:34 ` Chris Lattner
2002-04-29 8:30 Robert Dewar
2002-04-29 8:57 ` Chris Lattner
2002-04-29 8:30 Chris Lattner
2002-04-29 9:23 ` Daniel Berlin
2002-04-29 9:52 ` Chris Lattner
2002-04-29 9:58 ` Mark Dettinger
2002-04-29 5:18 Robert Dewar
2002-04-29 5:44 ` Mark Dettinger
2002-04-29 3:59 Mark Dettinger
2002-04-26 5:16 Mark Dettinger
2002-04-26 11:20 ` Joseph S. Myers
2002-04-26 12:59 ` Jakub Jelinek
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