Regarding critical fft bug

[Kate Minola]

Two questions regarding the critical bug in FFT multiply
code and the recommendation that gmp be recompiled with
--disable-fft.

1. Is there a way to check if an installation of gmp has
been built with --disable-fft?

By looking in gmp.h, I can find the version number of the
installed gmp.  Is there something similar for
--disable-fft?  Or is there some code I can run to check if
the bug is present in an installation of gmp?

2. What size of numbers does this bug affect?

For example, if I have been doing computations with numbers
with 100 decimal digits, should I go back and redo the
computations because the fft bug might have affected the
computations?

Kate Minola
Engineering Department
University of Maryland, College Park