Subject: Re: IEEE_754 logic
From: Thomas Hoffmann (firstname.lastname@example.org)
Date: Mon 18 Oct 1999 - 18:30:15 EST
> >>>>> Peter Dalgaard BSA writes:
> > > Thomas Hoffmann <email@example.com> writes:
> >> 3. The C9x draft introduces
the is*() functionality under the name of "classification MACROS". If an
> >>implementation implements this standard, autoconf misses isnan() and isfinite().
The problem for me is, that if isnan and isfinite are the way C9x says (i.e.
are MACROS), then configure concludes "not there" (AC_FUNCS misses macros
>From this it reasons "not IEEE 754".
Then I get back to a native finite() in Arith.h, but IEEE 754 mode was switched
So I see two topics:
1. Maybe not to (only) check if isnan/isfinite are library functions, but also
to check for working macros (I have not found a predefined macro in Autoconf for
This seems of some importance to me, because it is not only an idiosyncracy of a
singular system, but may become a more widespread problem if systems become C9x
2. Introduce a more bulletproof check for IEEE 754.
Is there possibly a computation we can carry out and conclude from its result to
IEEE 754? I just have no idea.
Thomas Hoffmann, Institut fuer Halbleiter- und Mikrosystemtechnik, TU Dresden
r-devel mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or "[un]subscribe"
(in the "body", not the subject !) To: firstname.lastname@example.org
This archive was generated by hypermail 2b25 : Tue 04 Jan 2000 - 14:16:09 EST