- Any extended integer types that exist in the implementation (6.2.5).
- Whether signed integer types are represented using sign and magnitude,
two's complement, or one's complement, and whether the extraordinary value
is a trap representation or an ordinary value (6.2.6.2).
GCC supports only two's complement integer types, and all bit patterns are ordinary values.

- The rank of any extended integer type relative to another extended integer type with the same precision (6.3.1.1).
- The result of, or the signal raised by, converting an integer to a signed integer type when the value cannot be represented in an object of that type (6.3.1.3).
- The results of some bitwise operations on signed integers (6.5).