%CHECK built-in function returns the first position of the string Base that contains a character that does NOT appear in string Comparator. If all of the characters in Base are also in Comparator, this function returns 0.
%CHECK (Comparator, Base, {Start})
Required. Can be a field name, array element, named constant, data structure name, data structure subfield name, literal, or table name; to compare against Base.
Required. Can be any valid numeric or character expression to compare with Comparator, and must be of the same type as Comparator.
Optional. Contains the position, relative to the leftmost position in Base, in which to start. If specified, Start must be a non-float numeric with zero decimal positions. If not specified, the starting position defaults to 1.
Checking begins at the Start or leftmost position of Base and continues character by character left to right. Each character of Base is compared with the Comparator characters and if a match exists, the next Base character is checked. If no match is found, the function returns the position within Base of the non-matched character. If all of the characters in Base are also in Comparator, this function returns 0.
The %CHECK command cannot accept *BOOLEAN and *IND data types.