^ISO/IEC 9899:2011. International Organization for Standardization. [2020-03-08]. (原始内容存档于2020-03-28) (英语). §6.2.5/6: For each of the signed integer types, there is a corresponding (but different) unsigned integer type (designated with the keyword unsigned) that uses the same amount of storage (including sign information) and has the same alignment requirements.
^ISO/IEC 9899:2011. International Organization for Standardization. [2020-03-08]. (原始内容存档于2020-03-28) (英语). §6.2.5/9: A computation involving unsigned operands can never overflow,because a result that cannot be represented by the resulting unsigned integer type is reduced modulo the number that is one greater than the largest value that can be represented by the resulting type.