"char" vs. "signed char" vs. "unsigned char" in rule 10.5

[andersl]

In C, there are three types of characters: "char", "signed char", and "unsigned char". (The representation of the type "char" is either signed or unsigned). Note that this makes characters different than the other integer types as, for example, "short" is a synonym for "signed short".

Rule 10.5 states "if the bitwise operators ~ and