OpenVMS usage:longword_unsigned
    type:         longword (unsigned)
    access:       write only
    mechanism:    by value

    The values returned by STR$COMPARE and the conditions to which
    they translate are as follows:

    Returned
    Value         Condition

    0             The length and the contents of first-source-string
                  are equal to the length and contents of second-
                  source-string.
    1             Either the length of first-source-string is not
                  equal to the length of second-source-string, or the
                  contents of first-source-string are not equal to
                  the contents of second-source-string, or both.