Date: Wed, 30 Jun 1999 10:39:10 -0500 From: Dan Nelson <dnelson@emsphone.com> To: Jos Backus <Jos.Backus@nl.origin-it.com> Cc: freebsd-hackers@FreeBSD.ORG, Tobi Oetiker <tobi@caida.org> Subject: Re: [tobi@caida.org: Re: [MRTG-DEV] CDEF's with LT and IF in .42] Message-ID: <19990630103910.B50144@dan.emsphone.com> In-Reply-To: <19990630151551.C51182@hal.mpn.cp.philips.com>; from "Jos Backus" on Wed Jun 30 15:15:51 GMT 1999 References: <19990630151551.C51182@hal.mpn.cp.philips.com>
next in thread | previous in thread | raw e-mail | index | archive | help
In the last episode (Jun 30), Jos Backus said: > ----- Forwarded message from Tobi Oetiker <tobi@caida.org> ----- > > OK found your problem .... it is that old FreeBSD does no proper > > IEEE math ... > > > > for some comparison operations it raises an sigfpe if an NaN is > > involved ... > > > > the next release of rrdtool will come with a proper test to find > > the problem and a proper fix in the software to ignore sigfpe > > Saw this on the MRTG-DEV list. > NaN handling is perceived to be problematic, it seems. The last time this came up (and it comes up every 6 months or so), the consensus was that we would rather trap FP errors than blindly pass them on to the user application. If a program wants to ignore NaN, divide-by-zero, underflow, and overflow conditions, let it wrap the offending line of code with two fpsetmask() calls; one to mask the condition, and one to restore the previous mask. If you want to completely ignore floating point errors, call fpsetmask(0) at the top of main(). I scanned the mailinglists and the thread that covers this issue most completely is http://www.freebsd.org/cgi/mid.cgi?id=199710101907.OAA09470@millenia.srrc.usda.gov -Dan Nelson dnelson@emsphone.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?19990630103910.B50144>