[Numpy-discussion] Slightly off-topic - accuracy of C exp function?

[Matthew Brett]

Hi,

I'm exploring Mingw-w64 for numpy building, and I've found it gives a
slightly different answer for 'exp' than - say - gcc on OSX.

The difference is of the order of the eps value for the output number
(2 * eps for a result of ~2.0).

Is accuracy somewhere specified for C functions like exp?  Or is
accuracy left as an implementation detail for the C library author?

Cheers,

Matthew