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

 floating-point-input-value

    OpenVMS usage:floating_point
    type:         F_floating, D_floating, G_floating
    access:       read only
    mechanism:    by reference

    The input value. The floating-point-input-value argument is
    the address of a floating-point number. For MTH$EXP, floating-
    point-input-value specifies an F-floating number. For MTH$DEXP,
    floating-point-input-value specifies a D-floating number. For
    MTH$GEXP, floating-point-input-value specifies a G-floating
    number.