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From: Szabolcs Nagy <nsz@port70.net>
To: musl@lists.openwall.com
Subject: Re: valgrind problems
Date: Sun, 16 Jun 2013 21:25:47 +0200	[thread overview]
Message-ID: <20130616192546.GG6548@port70.net> (raw)
In-Reply-To: <1371405720.5692.129.camel@eris.loria.fr>

* Jens Gustedt <jens.gustedt@inria.fr> [2013-06-16 20:02:00 +0200]:
> as I said up-thread, this is not my own opinion (I personally would
> argue as you do) but expressed in a recent discussion on the list of
> the C standards committee. In addition there is an 10 year old reply
> to a DR that goes in that direction.

i see

> And to clarify that, this is not about UB, but about the stability of
> the value.

i don't see any way "unstable" value can be allowed in c
without invoking UB

objects have to retain their last stored value or their
initial value
(so object access cannot be unstable)

the abstract machine is defined in terms of sequencing
side effects and value computations
(so indeterminate values can only have unstable meaning
if all operators have well defined semantics for them:
eg. the semantics of '+' should say that the value of
the result is the sum of the operands or indeterminate
if any of the operands is indeterminate)


  reply	other threads:[~2013-06-16 19:25 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-06-15 22:01 [PATCH] bugfix: initialize a state variable in lio_wait Jens Gustedt
2013-06-15 22:16 ` Szabolcs Nagy
2013-06-16  5:40   ` Rich Felker
2013-06-16  7:22     ` Jens Gustedt
2013-06-16  9:31       ` Jens Gustedt
2013-06-16 10:18         ` Justin Cormack
2013-06-16 10:43           ` valgrind problems Jens Gustedt
2013-06-16 11:39             ` Szabolcs Nagy
2013-06-16 14:16               ` Jens Gustedt
2013-06-16 14:36                 ` Rich Felker
2013-06-16 14:31             ` Rich Felker
2013-06-16 15:26               ` Jens Gustedt
2013-06-16 15:31                 ` Rich Felker
2013-06-16 15:58                   ` Jens Gustedt
2013-06-16 16:04                     ` Rich Felker
2013-06-16 17:39                       ` Jens Gustedt
2013-06-16 19:16                         ` Rich Felker
2013-06-16 19:38                           ` Szabolcs Nagy
2013-06-16 19:41                             ` Rich Felker
2013-06-16 17:40                     ` Szabolcs Nagy
2013-06-16 18:02                       ` Jens Gustedt
2013-06-16 19:25                         ` Szabolcs Nagy [this message]
2013-06-16 19:29                           ` Rich Felker
2013-06-16 14:24         ` [PATCH] bugfix: initialize a state variable in lio_wait Rich Felker
2013-06-16 15:48           ` Jens Gustedt
2013-06-16 15:37   ` Szabolcs Nagy

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