The ANY LENGTH clause specifies that the length of a linkage section item may vary at runtime and is determined by the length of the argument.
ANY LENGTH
Note: The ANY LENGTH clause is not permitted to be specified in an outermost program. This is because an outermost program can be called with or without a program-prototype format CALL statement. For calls without a program-prototype, the implementation is not able to determine whether an argument corresponds to a formal parameter described with ANY LENGTH.