mpz_invert (x, 1, 0)
tg at gmplib.org
Sat Mar 3 19:00:42 CET 2012
bodrato at mail.dm.unipi.it writes:
Again, Niels propose an elegant way out: we can let inverses mod 0
undefined. To obtain this we can keep the old library code, and patch only
the recent testing program and documentation.
I vote for this option.
"The behaviour of computations modulo 0 is defined as being undefined."
What should we do with mpz_powm, and mpz_powm_ui? The code for both
functions starts with:
n = ABSIZ(m);
if (n == 0)
Would you want to change that?
Just because something is undefined, does not mean we have to expose
users to some release-for-release changing crash. Predictably crashing
in a way that can be caugth (by means of signal handling) is best.
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