/sys$common/syshlp/helplib.hlb RTL Routines, MTH$, MTH$HATAN, Arguments  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 h-radians

    OpenVMS usage:floating_point
    type:         H_floating
    access:       write only
    mechanism:    by reference

    Angle (in radians) whose tangent is specified by tangent. The
    h-radians argument is the address of an H-floating number that
    is this angle. MTH$HATAN writes the address of the angle into
    h-radians.

 tangent

    OpenVMS usage:floating_point
    type:         H_floating
    access:       read only
    mechanism:    by reference

    The tangent of the angle whose value (in radians) is to be
    returned. The tangent argument is the address of a floating-point
    number that is this tangent. For MTH$HATAN, tangent specifies an
    H-floating number.