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

Funny thing, people asked that same question on comp.std.c in 1993, and nobody could point to a one's complement machine that had been used back then.

So yes, I think we can confidently say that one's complement belongs to a dark corner of our history, practically dead, and is not a concern anymore.