VMS Help RTL Routines, MTH$, MTH$CEXP, Argument  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 complex-number

    OpenVMS usage:complex_number
    type:         F_floating complex
    access:       read only
    mechanism:    by reference

    Complex number whose complex exponential is to be returned. This
    complex number has the form (r,i), where r is the real part and i
    is the imaginary part. The complex-number argument is the address
    of this complex number. For MTH$CEXP, complex-number specifies an
    F-floating number.