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bug#11825: 24.1.50; float-time no longer accepts negative time values
From: |
Eli Zaretskii |
Subject: |
bug#11825: 24.1.50; float-time no longer accepts negative time values |
Date: |
Mon, 09 Jul 2012 05:56:21 +0300 |
> Date: Sun, 08 Jul 2012 16:03:39 -0700
> From: Paul Eggert <eggert@cs.ucla.edu>
> CC: Eli Zaretskii <eliz@gnu.org>, 11825@debbugs.gnu.org
>
> On 07/08/2012 02:00 AM, Andreas Schwab wrote:
> > A difference between two timestamps is always signed.
>
> No, not if A is an absolute time, and B is a (nonnegative) offset.
> The result is an absolute time, and is unsigned if A was unsigned.
> For example:
>
> EMACS_GET_TIME (t);
> EMACS_SUB_TIME (old, t, EMACS_TIME_FROM_DOUBLE (delay));
>
> This is a common way that EMACS_SUB_TIME is used in Emacs.
Again, if this facility is limited to this paradigm, I think we should
clearly document that. The name EMACS_SUB_TIME doesn't tell anything
about that, it certainly sounds like providing a general-purpose
arithmetics on time values.
Anyway, Emacs does subtract absolute time values, at least in Lisp;
see time-subtract. The current issue started when the result of
time-subtract was passed to float-time, so indirectly such time
differences can sneak into C from Lisp and be handed to these
functions. And since time-subtract is called by timers, it is very
easy to get into a situation where EMACS_SUB_TIME etc. are used with
second argument not an offset, but an absolute time.
> > this should be prominently explained in systime.h.
>
> OK, sure, I pushed this:
Thanks.
- bug#11825: 24.1.50; float-time no longer accepts negative time values, (continued)
- bug#11825: 24.1.50; float-time no longer accepts negative time values, Paul Eggert, 2012/07/06
- bug#11825: 24.1.50; float-time no longer accepts negative time values, Eli Zaretskii, 2012/07/07
- bug#11825: 24.1.50; float-time no longer accepts negative time values, Paul Eggert, 2012/07/07
- bug#11825: 24.1.50; float-time no longer accepts negative time values, Eli Zaretskii, 2012/07/07
- bug#11825: 24.1.50; float-time no longer accepts negative time values, Paul Eggert, 2012/07/08
- bug#11825: 24.1.50; float-time no longer accepts negative time values, Andreas Schwab, 2012/07/08
- bug#11825: 24.1.50; float-time no longer accepts negative time values, Paul Eggert, 2012/07/08
- bug#11825: 24.1.50; float-time no longer accepts negative time values, Juanma Barranquero, 2012/07/08
- bug#11825: 24.1.50; float-time no longer accepts negative time values, Paul Eggert, 2012/07/08
- bug#11825: 24.1.50; float-time no longer accepts negative time values, Juanma Barranquero, 2012/07/08
- bug#11825: 24.1.50; float-time no longer accepts negative time values,
Eli Zaretskii <=
- bug#11825: 24.1.50; float-time no longer accepts negative time values, Paul Eggert, 2012/07/08
- bug#11825: 24.1.50; float-time no longer accepts negative time values, Eli Zaretskii, 2012/07/08