invo_context

    OpenVMS usage:invo_context_blk
    type:         structure
    access:       modify
    mechanism:    by reference

    Address of a valid invocation context block.

 index

    OpenVMS usage:index
    type:         longword
    access:       read
    mechanism:    by value

    Index into the FREG array of the invocation context block.

 fr_copy

    OpenVMS usage:floating-point value
    type:         octaword
    access:       write
    mechanism:    by value

    Address of an octaword that contains the floating-point value to
    be written to the invocation context block.