OpenVMS usage:complex_number
    type:         D_floating complex, G_floating complex, IEEE
                  S_floating complex, IEEE T_floating complex,
    access:       write only
    mechanism:    by value

    Complex result of multiplying two complex numbers. OTS$MULCD_
    R3 returns a D-floating complex number. OTS$MULCG_R3 returns a
    G-floating complex number. OTS$MULCS returns an IEEE S-Floating
    complex number. OTS$MULCT_R3 returns an IEEE T-floating complex
    number.