7.18.1 Integer types
When typedef names differing only in the absence or presence of the initial u are defined, they shall denote corresponding signed and unsigned types as described in 6.2.5; an implementation providing one of these corresponding types shall also provide the other.
In the following descriptions, the symbol N represents an unsigned decimal integer with no leading zeros (e.g., 8 or 24, but not 04 or 048).