invo_context OpenVMS usage:invo_context_blk type: structure access: read mechanism: by reference Address of a valid invocation context block. index OpenVMS usage:index type: longword access: read mechanism: by value Floating point register index. fr_copy OpenVMS usage:floating-point value type: octaword access: write mechanism: by value Address of an octaword to receive the contents of the specified floating-point register.