The UVALID Function

If a character string consists of valid Unicode UTF-8 or UTF-16 data, the UVALID function returns the value zero. If a character string contains invalid Unicode data, the UVALID function returns the index of the first invalid element.

The function type is integer.

General Format

Arguments

argument-1: Must be alphabetic, alphanumeric, or national.

Returned Values

The returned value is an integer, which differs based on argument-1:

If argument-1 is of class alphabetic or alphanumeric, and it consists of valid UTF-8 encoded Unicode data, the returned value is zero.
If argument-1 is of class alphabetic or alphanumeric, and it contains invalid UTF-8 encoded Unicode data, the returned value is the position of the first byte where the invalid UTF-8 data starts.
If argument-1 is of class national, and it consists of valid UTF-16 encoded Unicode data, the returned value is zero.
If argument-1 is of class national, and it contains invalid UTF-16 encoded Unicode data, the returned value is the position of the first UTF-16 encoding unit where the invalid UTF-16 data starts. This position is one plus the number of well-formed UTF-16 encoding units that precede the invalid data.

Note: The UVALID function indicates whether the character string contains well-formed Unicode UTF-8 or UTF-16 data. It does not indicate whether any or all of the Unicode code points represented by the character string are assigned to characters.