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

    Given the tangent of an angle, the Arc Tangent in Radians routine
    returns that angle (in radians).

    Format

      MTH$ATAN  tangent

      MTH$DATAN  tangent

      MTH$GATAN  tangent

      Each of the above formats accepts one of the floating-point
      types as input.

1 - Corresponding JSB Entry Points

      MTH$ATAN_R4

      MTH$DATAN_R7

      MTH$GATAN_R7

      Each of the above JSB entry points accepts one of the floating-
      point types as input.

2 - Returns

    OpenVMS usage:floating_point
    type:         F_floating, D_floating, G_floating
    access:       write only
    mechanism:    by value

    Angle in radians. The angle returned will have a value in the
    range:

    MTH$ATAN returns an F-floating number. MTH$DATAN returns a D-
    floating number. MTH$GATAN returns a G-floating number.

3 - Argument

 tangent

    OpenVMS usage:floating_point
    type:         F_floating, D_floating, G_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$ATAN, tangent specifies an
    F-floating number. For MTH$DATAN, tangent specifies a D-floating
    number. For MTH$GATAN, tangent specifies a G-floating number.