Validating data
If you suspect that your program is trying to perform arithmetic on nonnumeric data or is receiving the wrong type of data on an input record, use the class test (the class condition) to validate the type of data.
About this task
You can use the class test to check whether the content
of a data item is ALPHABETIC, ALPHABETIC-LOWER, ALPHABETIC-UPPER, DBCS, KANJI,
or NUMERIC. If the data item is described
implicitly or explicitly as USAGE NATIONAL, the class
test checks the national character representation of the characters
associated with the specified character class.
You can use the UVALID intrinsic function
to check whether a national data item contains valid UTF-16 encoded
data, or whether an alphanumeric or alphabetic item contains valid
UTF-8 encoded data.
Class condition (Enterprise COBOL for z/OS® Language Reference)
UVALID (Enterprise COBOL for z/OS Language Reference)