library_index

    OpenVMS usage:longword_unsigned
    type:         longword (unsigned)
    access:       read only
    mechanism:    by reference
    Library control index returned by the LBR$INI_CONTROL library
    routine. The library_index argument is the address of the
    longword that contains the index.

 ret_va_addr

    OpenVMS usage:address
    type:         quadword address
    access:       write only
    mechanism:    by 32-bit or 64-bit reference
    The 32-bit or 64-bit virtual address of a naturally aligned
    quadword into which the routine returns the virtual address at
    which the routine mapped the library module.

 ret_mod_len

    OpenVMS usage:byte_count
    type:         quadword (unsigned)
    access:       read only
    mechanism:    by reference
    The address of a naturally aligned quadword into which the
    library routine returns the module length.

 txtrfa

    OpenVMS usage:vector_longword_unsigned
    type:         longword (unsigned)
    access:       read only
    mechanism:    by reference
    The module's record file address (RFA) of the library module
    header. The txtrfa argument is the address of the 2-longword
    array that specifies the RFA of the module header.