You shouldn't have to worry - there aren't too many ones complement machines out there :)
But the easiest thing might be to compare "-1" with ~0.
Question
What is the most reliable way to detect whether the architecture uses one's or two's complement representation in C++?
Solution
You shouldn't have to worry - there aren't too many ones complement machines out there :)
But the easiest thing might be to compare "-1" with ~0.