Date: Sun, 17 Mar 2002 00:44:43 +1100 (EST) From: Bruce Evans <bde@zeta.org.au> To: Tadayuki OKADA <tadayuki.okada@windriver.com> Cc: Tadayuki OKADA <tokada@isi.com>, <standards@freebsd.org> Subject: Re: _MULTI_LIBM Message-ID: <20020317001529.T30317-100000@gamplex.bde.org> In-Reply-To: <3C922061.DD01E0B@windriver.com>
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On Fri, 15 Mar 2002, Tadayuki OKADA wrote:
> Bruce Evans wrote:
> > > It's not POSIX complient nor ANSI.
> >
> > It is now :-). C99 supports IEEE754, and doesn't require math functions
> > to set errno.
> In this respect, yes. But other portion of FreeBSD is not (yet),
> so we can't say FreeBSD is C90 complient or C99.
>
> BTW, why don't we just define math_errhandling, MATH_ERRNO and
> MATH_ERREXCEPT in math.h for POSIX complience for now?
> Or are we waiting for fenv.h?
I didn't know about math_errhandling, MATH_ERRNO or MATH_ERREXCEPT.
They seem to be new in POSIX.1-2001 (they aren't in POSIX-1.1996 or
C99). math_errhandling seems to be settable by the implemenation only.
They are bugs in POSIX IMO. C99 got rid of the broken-as-designed
requirement to set errno, but POSIX increased it (in practice). From
POSIX-1.200x-draft7:
3861 APPLICATION USAGE
3862 On error, the expressions (math_errhandling & MATH_ERRNO) and (math_errhandling &
3863 MATH_ERREXCEPT) are independent of each other, but at least one of them must be non-zero.
I'm not sure if the application can set math_handling. So, POSIX now
gives the alternatives of MATH_ERRNO being set (this means that math
functions must set errno for all types if "errors" (not just for range
errors as required by C90)), or MATH_ERREXCEPT being set (this means
that math functions must cause exceptions as not permitted by C9*, but
as FreeBSD on i386's used to do).
I'm certainly waiting for fenv.h :-).
Bruce
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