On 14 August 2017 at 09:22, Toebs Douglass wrote: > I understand what it means in general, but I'm surprised by that it can > happen; I've not heard of it before. To make sure I understand - this is a > kind of run-time error, like divide by zero? See 3.19.4 and 3.19.5 in the C standard (you can see the Terms & Definitions in the https://www.iso.org/obp/ui/#iso:std:iso-iec:9899:ed-3:v1:en preview on the ISO site).