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From: Marius Vollmer <m.vollmer@ping.de>
Cc: Bill Schottstaedt <bil@ccrma.stanford.edu>,
	Carl Witty <cwitty@newtonlabs.com>,
	guile-devel@gnu.org
Subject: Re: scm_i_fraction_reduce thread safety
Date: Wed, 21 Jan 2004 01:03:33 +0100	[thread overview]
Message-ID: <87ad4ikw16.fsf@zagadka.ping.de> (raw)
In-Reply-To: <40022F15.30903@vzavenue.net> (Richard Todd's message of "Sun, 11 Jan 2004 23:22:29 -0600")

Richard Todd <richardt@vzavenue.net> writes:

> 1) If you are worried about thread safety, the most fool-proof C
> interface probably does not allow separate access to numerator and
> denominator, since they need to be read in one atomic operation to
> ensure consistent results in the face of other mutating code.

Guile fractions can not mutated in general: they always represent one
value.  The mutation that might take place is a reduction, but that
might only happen once.  After a fraction is reduced, it stays that
way.  So when you have a reduced fraction you can safely return the
nominator, say, without having to worry that a later access to the
denominator will return something bogus.

-- 
GPG: D5D4E405 - 2F9B BCCC 8527 692A 04E3  331E FAF8 226A D5D4 E405


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  parent reply	other threads:[~2004-01-21  0:03 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-12-11 11:43 scm_i_fraction_reduce thread safety Bill Schottstaedt
2003-12-11 19:19 ` Carl Witty
2003-12-12 12:11   ` Bill Schottstaedt
2003-12-12 15:04   ` Paul Jarc
2003-12-12 23:23   ` Kevin Ryde
2004-01-10 22:38     ` Marius Vollmer
2004-01-10 23:29       ` Kevin Ryde
2004-01-11  1:31         ` Marius Vollmer
2004-01-12  0:51           ` Kevin Ryde
2004-01-12  5:22             ` Richard Todd
2004-01-14 21:09               ` Kevin Ryde
2004-01-21  0:03               ` Marius Vollmer [this message]
2004-01-21  0:00             ` Marius Vollmer
2004-01-21  3:11               ` Carl Witty
2004-01-21 21:06                 ` Marius Vollmer
2004-01-27 22:15                 ` Dirk Herrmann
2004-01-27 23:24                   ` Rob Browning
2004-01-29 19:35                     ` Marius Vollmer
2004-01-29 20:32                       ` Rob Browning
2004-01-30 14:45                       ` Mikael Djurfeldt
2004-02-01 18:49                         ` Andy Wingo
  -- strict thread matches above, loose matches on Subject: below --
2003-12-09 20:39 Kevin Ryde

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