A zero-length item is a data item whose minimum permissible length is 0 and whose length at runtime is 0. A zero-length item is one of the following:
A group item containing only data items which are described with OCCURS DEPENDING ON, and the number of repetitions is 0.
A group item which is subordinate only to zero-length items.
A data item which is defined with ANY LENGTH and corresponds to an argument or return value which is a zero-length item.
A record of a file with variable record format in which the number of character positions is 0.
An internal standard function which returns a zero-length result.
Special registers XML-TEXT, XML-NAMESPACE, XML-NAMESPACE-PREFIX or XML-NTEXT, XML-NNAMESPACE, XML-NNAMESPACE-PREFIX if they are not assigned a value (see section "Special registers for the XML PARSE statement").