Is one's complement a real-world issue, or just a historical one?

Question

Another question asked about determining odd/evenness in C, and the idiomatic (x & 1) approach was correctly flagged as broken for one\'s complement-based systems, which

Answer 1

The CDC Cyber 18 I used back in the '80 was a 1s complement machine, but that's nearly 30 years ago, and I haven't seen one since (however, that was also the last time I worked on a non-PC)