NAME
	  glGetClipPlane - return the coefficients of the specified
	  clipping plane


     C SPECIFICATION
	  void glGetClipPlane( GLenum plane,
			       GLdouble	*equation )


     PARAMETERS
	  plane	    Specifies a	clipping plane.	 The number of
		    clipping planes depends on the implementation, but
		    at least six clipping planes are supported.	 They
		    are	identified by symbolic names of	the form
		    GL_CLIP_PLANEi where 0 < i < GL_MAX_CLIP_PLANES.

	  equation  Returns four double-precision values that are the
		    coefficients of the	plane equation of plane	in eye
		    coordinates.  The initial value is (0, 0, 0, 0).

     DESCRIPTION
	  glGetClipPlane returns in equation the four coefficients of
	  the plane equation for plane.

     NOTES
	  It is	always the case	that GL_CLIP_PLANEi = GL_CLIP_PLANE0 +
	  i.

	  If an	error is generated, no change is made to the contents
	  of equation.

     ERRORS
	  GL_INVALID_ENUM is generated if plane	is not an accepted
	  value.

	  GL_INVALID_OPERATION is generated if glGetClipPlane is
	  executed between the execution of glBegin and	the
	  corresponding	execution of glEnd.

     SEE ALSO
	  glClipPlane