On Mon, Mar 12, 2012 at 12:47 PM, Bruno Haible <br...@clisp.org> wrote: >> In November 2011, I wrote in >> <http://lists.gnu.org/archive/html/bug-gnulib/2011-11/msg00069.html>: >> >> glibc 2.11: NaN, fenv bit, errno >> MacOS X 10.5: NaN, fenv bit math_errhandling >> (always=MATH_ERREXCEPT) >> FreeBSD 6.4: NaN, fenv bit math_errhandling >> (always=MATH_ERREXCEPT) >> OpenBSD 4.9: NaN >> NetBSD 5.1: NaN, errno >> AIX 7.1: NaN, fenv bit, errno math_errhandling (always=MATH_ERRNO) >> HP-UX 11.31: NaN, fenv bit, errno >> IRIX 6.5: NaN >> OSF/1 5.1: 0, errno (<fenv.h> incomplete) >> Solaris 10: NaN, fenv bit, errno math_errhandling >> (always=MATH_ERREXCEPT) >> Cygwin 1.7.9: NaN, errno >> mingw: NaN, fenv bit, errno >> MSVC 9: NaN, errno > > Actually glibc does not support the 'errno' convention really. > See this list of bugs: [1] > The following are still open: > 6796 fdim() does not set errno on overflow > 6785 erf() does not set errno for underflow > 6793 logb() does not set errno on pole error > 6804 scalb() does not set errno on domain error > 6808 yn() does not set errno for overflow error. > 6802 remquo() does not set errno on domain error > 6792 log1p() does not set errno n error > 6801 fma() does not ser errno for various errors > 6797 lround() and llround() do not set errno on domain error > 6786 erfc() does not set errno for underflow > 6798 lrint() and llrint() do not set errno on domain error > 6810 tgamma() does not set errno for underflow error > 6809 tgamma() sets errno inconsistently for domain error > 6795 hypot() does not set errno consistently on error > 6787 exp10() does not consistently set errno > 6799 nextafter() and nexttoward() doen't set errno on overflow/underflow > errors > 6807 y0(), y1(), yn() do not raise exception and give wrong errno for pole > error > 6794 ilogb() does not raise exceptions or set errno on domain errors > 6803 scalb(), scalbln(), scalbn() do not set errno on overflow/underflow > 6805 j0(), j1(), jn() do not raise exceptions on underflow error > 6806 y0(), y1(), yn() do not raise exception on underflow > > If glibc does not support this error reporting convention, I think there's > not much point for gnulib to do it.
We must a least document it. I have been beaten by y0 underflow a few times... > > Btw, a side note about the "fenv bit" convention: > 1) "inexact" and "underflow" exceptions cannot be taken seriously > because Joseph Myers sais [2]: > "C99 and C11 permit spurious underflow exceptions (as well as > spurious inexact exceptions, and raising inexact even when > the result is exact)." > 2) glibc has some open bugs in this area as well: [3] 1) is a quality of implementation bug and should be closed. 2) will try to submit paches Bastien > Bruno > > [1] > http://sourceware.org/bugzilla/buglist.cgi?query_format=specific&order=relevance%20desc&bug_status=__all__&content=math%20errno&list_id=3078 > [2] http://sourceware.org/bugzilla/show_bug.cgi?id=6778 > [3] http://sourceware.org/bugzilla/show_bug.cgi?id=13787 > >
