OUTCUR ( curve, cutype, vec1, vec2, vec3, d1, d2, ifail )
=========================================================

  Output curve.

    Can be called from the GO.

Receives:
  KI_tag_curve             *curve          --- curve to be output

Returns:
  KI_cod_tycu              *cutype         --- type of curve
  KI_vec                    vec1           --- first vector defining curve
  KI_vec                    vec2           --- second vector defining curve
  KI_vec                    vec3           --- third vector defining curve
  double                   *d1             --- first double defining curve
  double                   *d2             --- second double defining curve
  KI_cod_error             *ifail          --- failure code

Specific errors:
  KI_wrong_sub_type         not a curve supported by this routine

Description:
  The type-code of the curve, from the range TYCU00, indicates
  how to interpret the remaining values as follows:

  Type                     Argument     Definition
  =======================================================
  Straight line   (TYCUST) 'vec1'         position on line
                           'vec2'         direction of line

  Circle          (TYCUCI) 'vec1'         centre
                           'vec2'         axis direction
                           'd1'           radius

  Ellipse         (TYCUEL) 'vec1'         centre
                           'vec2'         major axis
                           'vec3'         minor axis
                           'd1'           major radius
                           'd2'           minor radius

  Intersection    (TYCUIN) 'vec1'         start of curve
                           'vec2'         end of curve

  For other curve types only the type-code is returned.  Use this code
  to select the appropriate output routine.

  Arguments surplus to an above curve definition are set to zero.