Mandrake vs glibc (was RE: [Python-Dev] RE: Possible bug (was Re: numpy, overflow, inf, ieee, and rich comparison)
Fri, 13 Oct 2000 16:23:31 -0400
The original source of my concern was this c.l.py post from David Cooke:
He ran a little C program that Huaiyu Zhu had posted earlier in the thread.
According to David's results, under "Linux-Mandrake 7.1 (glibc 2.1.3) ...
without -lieee, but compiled with -O ... gcc 2.95.2.", platform exp and sqrt
*never* set errno, regardless of input. In which case what Python does with
the platform NaN result from math.sqrt(-1.) is an accident (and probably
ends up setting errno to ERANGE itself by mistake), and an overflowing exp
would let the platform +Inf result pass thru silently.
So, if David's report is correct, and best I understand it you were all
using 7.1 too with at least some level of optimization, it's A Mystery why
CVS test_math.py succeeds on that system (its new math.sqrt(-1) test would
probably fail; its new math.exp(+huge) test would almost certainly fail).
I'm anal enough about this stuff that I'd try to figure out why if I had a
Mandrake system, but in the cosmic scheme of things I doubt it's important
enough for anyone else to burn time on.