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Re: (elisp)Numbers


From: Eli Zaretskii
Subject: Re: (elisp)Numbers
Date: Tue, 21 Oct 2003 07:38:56 +0200

> Date: Mon, 20 Oct 2003 21:29:16 -0500 (CDT)
> From: Luc Teirlinck <address@hidden>
> 
> 1.  In (elisp)Numeric Conversions, is it worth pointing out that not
>     only `floor', but also `truncate', `ceiling' and `round' take an
>     optional DIVISOR argument?

IMHO, yes.

> 2.  In (elisp)Math Functions, it is said that asin, acos, log, log10
>     and sqrt all return NaN values for out-of-range arguments, but, on
>     my machine, only `sqrt' does.  The others throw an error, see the
>     IELM run below.  Is this machine dependent?

Yes, see the commentary at the beginning of src/floatfns.c, in
particular the HAVE_MATHERR and the various FLOAT_CHECK_* macros.  The
bottom line is that the details depend on the specific implementation
of handling abnormal arguments by the system libraries.  (Btw, I
expect the bahavior we see today to change over the next years, as C9x
propagates with its new requirements about FP exceptions.)




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