Date: Sun, 17 Mar 2002 12:24:25 +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: <20020317113138.E34997-100000@gamplex.bde.org> In-Reply-To: <3C93C9C5.F085857A@windriver.com>
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On Sat, 16 Mar 2002, Tadayuki OKADA wrote: > Bruce Evans wrote: > > > 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? > ... > > They are bugs in POSIX IMO. C99 got rid of the broken-as-designed > > requirement to set errno, but POSIX increased it (in practice). > No, new POSIX just requires one of 'errno' or 'exception' error handling > must be present. You don't need to set 'errno', but then you have to > have exception handling defined in <fenv.h>. > I don't know if C99 mandates one of them to be present. C99 permits both but requires neither. Also, it specifies "exceptions" more clearly -- math errors may raise exceptions by just setting an exception flag; a SIGFPE for this is permitted but not required. There is no standard way to tell if you will get SIGFPE's. I think POSIX intends to say the same, but I couldn't find where it connects "floating-point exception" with "SIGFPE". > > 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). > MATH_ERREXCEPT means you can use fp-exception facility > defined in <fenv.h>, so it's not inconsistent with C99. OK. Bruce To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-standards" in the body of the message
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