[Python-Dev] 2.2.1c1 platform reports.

2002年3月22日 18:57:43 -0500

[Martin]
> Is that the final text? My copy says
>> On a domain error, the function returns an
> implementation-defined value; if the integer expression
> math_errhandling & MATH_ERRNO is nonzero, the integer
> expression errno acquires the value EDOM; if the integer
> expression math_errhandling & MATH_ERREXCEPT is nonzero, the
> ``invalid'' floating-point exception is raised.
>> but it comes from a draft only (99-04).

Mine also comes from a draft, dated 2000年08月07日. Jeremy bought the final
std, but good luck hassling him to look stuff up for us <wink>.
> If this is what C99 says, you actually can tell, in C, whether checking
> errno will help indicating the error.

And when it doesn't, we're back to guessing. We already take advantage of
sqrt(-1) setting EDOM on those platforms where it does. I don't see any
simplification.
> If the C implementation also implements Annex F, IEEE-754 fans should
> be satisfied, no?

Python doesn't know anything about Annex F now -- those facilities may as
well not exist given our current code. Python's users are in two very
different camps too: some want sqrt(-1) to blow up, and others want to get
back a NaN without exception. Similarly for overflow and divide-by-zero,
etc. C99 + Annex F is, from Python's current POV, just another unique
platform Python knows nothing about.