LIB$GET_LOGICAL provides a simplified interface to the $TRNLNM
    system service. It provides most of the features found in $TRNLNM
    with some additional benefits. For string arguments, all string
    classes supported by the Run-Time Library are understood. The
    list of item descriptors, which may be difficult to construct in
    high-level languages, is handled internally by LIB$GET_LOGICAL.

    See the description of the $TRNLNM system service in the HP
    OpenVMS System Services Reference Manual for more information.