signal-arguments
    OpenVMS usage:vector_longword_unsigned
    type:         unspecified
    access:       modify
    mechanism:    by reference, array reference
    Signal argument vector. The signal-arguments argument contains
    the address of an array that is this signal argument vector
    stack.
    See the HP OpenVMS Programming Concepts Manual for a description
    of the signal argument vector.
 mechanism-arguments
    OpenVMS usage:vector_longword_unsigned
    type:         unspecified
    access:       read only
    mechanism:    by reference, array reference
    Mechanism argument vector. The mechanism-arguments argument
    contains the address of an array that is this mechanism argument
    vector stack.
    See the HP OpenVMS Programming Concepts Manual for a description
    of the mechanism argument vector.