Valid Code Points
The range of Unicode code points is 0x0 to 0x10FFFF. However, some values within this range are reserved and are not valid characters. RWUCharTraits provides the static method RWUCharTraits::isCharacter(), which returns true if a given RWUChar32 value is a valid Unicode character code point.
RWUCharTraits::isDefined() returns true if a given value RWUChar32 is defined as the code point for a named character in the Unicode Character Database. A defined character is assigned various properties under the Unicode Standard. These properties can be accessed using other methods provided by RWUCharTraits, as described in the following sections.
RWUCharTraits::isCharacter()tests whether a code point is valid, and hence may be a defined character. RWUCharTraits::isDefined() tests whether a code point has already been defined.