Re: sqrt with negative arg.

[Eli Zaretskii]

> Date: Wed, 31 Dec 2003 15:36:31 -0600 (CST)
> From: Luc Teirlinck <address@hidden>
> 
> A few hours ago, the documentation of sqrt in numbers.texi was
> changed from saying that it returns a NaN to saying that it signals a
> domain-error.  It definitely returns a NaN on my machine.

Really?  What system is that?  Can you debug Fsqrt and see why it
happens?

The way it's supposed to work on most modern systems is that the call
to `sqrt' in the underlying C code causes errno to be set, and Fsqrt
is supposed to check for that and signal an appropriate error.  See
the macro IN_FLOAT defined on floatfns.c.

(The last time a similar problem was reported and discussed here, we
found it was due to a bug in a particular version of glibc that was
fixed in later versions.)