wn_axis_grid(_c)

	status.i4.v = wn_axis_grid(plane.i4.r, num_major.i4.r,
				   num_minor.i4.r, grid_it.i4.r
				   [,loc_major.r4a.r] [,tick_length.r4.r]
				   [,loc_minor.r4a.r] [,invert_ticks.i4.r]
				   [,grid_line_typ.i4.r])

	status.i4.v = wn_axis_grid_c(plane.i4.v, num_major.i4.v,
				     num_minor.i4.v, grid_it.i4.v
				     [,loc_major.r4a.r] [,tick_length.r4.r]
				     [,loc_minor.r4a.r] [,invert_ticks.i4.v]
				     [,grid_line_typ.i4.v])

	This routine draws axis lines and makes tick marks and optional
	grids on the active graphic window.  Note that the color of the
	axis and grid lines will be the color selected by the most recent
	call to wn_color(_c).

	plane 		axis for grid marks
			(WN_HORZ -> horizontal axis (bottom of window),
			 WN_VERT -> vertical axis (left side of window),
			 WN_HORZ_TOP -> horizontal axis (top of window),
			 WN_VERT_RIGHT -> vertical axis (right side of window))
	num_major 	number of spaces between major ticks/grids
	num_minor	number of spaces between minor ticks per major space
			(If "loc_minor" is specified and does not have a value
			 of NULL, "num_minor" indicates the total number of
			 minor tick mark values passed in "loc_minor".)
	grid_it 	grid flag
			(FALSE -> no grid,
			 TRUE -> grid on major ticks)
	[loc_major]	array ("num_major" + 1 elements) of real world
			coordinates defining locations for each major axis
			tick/grid mark  (Default is NULL which results
			in a simple division of the size of the window
			by the number of major ticks.)
	[tick_length]	length of tick marks in terms of the real world
			coordinates for the opposite plane to the axis plane
			(Default is NULL which results in a ratio of 0.04
			for the length of the tick marks relative to the
			entire width of the window.)
	[loc_minor]	array ("num_minor" + 1 elements) of real world
			coordinates defining locations for each minor axis
			tick mark  (Default is NULL which results in a
			simple division of the size of the window by the
			number of major ticks times the number of minor ticks.)
	[invert_ticks]	tick mark direction flag
			(FALSE -> draw tick marks on the inside of the
				  grid (default),
			 TRUE -> draw tick marks on the outside of the grid)
	[grid_line_typ]	type of line for major grid lines
			(WN_SOLID_LINE -> solid lines (default),
			 WN_DOTTED_LINE -> dotted lines)

	This function returns ACNET status values as follows:

	OK			success
	CBS_INVARG		invalid plane specified
	CBS_NOSETUP		an active window has not been established

	This function requires the following include files:

	cnsparam_h, cbslib_h, acnet_errors_h

	Related functions:

	wn_axis_label(_c), wn_grid(_c), wn_quick_grid, wn_flush,
	wn_redraw_grid_c, wn_color(_c), wn_user_defined_color_c,
	wn_read_user_defined_color, intro_graphics_windows

	C/C++ usage:

	int	status;
	int	plane = WN_HORZ;
	int	num_major = 4;
	int	num_minor = 5;
	int	grid_it = TRUE;
	int	invert_ticks = FALSE;
	int	grid_line_typ = WN_SOLID_LINE;
	float	*loc_major = (float *) NULL;
	float	*tick_length = (float *) NULL;
	float	*loc_minor = (float *) NULL;

	status = wn_axis_grid_c(plane,num_major,num_minor,grid_it.i4.v,
				loc_major,tick_length,loc_minor,
				invert_ticks,grid_line_typ);