When using cairo_svg_surface_create in exactly the same fashion as cairo_ps_surface_create (which has an identical API in the documentation) I get a warning from the former but never have for the latter:
assignment makes pointer from integer without a cast

Something seems to be either wrong with the documentation or the code for cairo_svg_surface_create; however, my program still functions fine anyway. It would be nice to not have the warning appear when compiling though.

Here is the code that uses it:

gboolean plot_linear_print_eps(GtkWidget *plot, gchar* fout)
{
	cairo_t *cr;
	cairo_surface_t *surface;

	surface=cairo_ps_surface_create(fout, (gdouble) (plot->allocation.width), (gdouble) (plot->allocation.height));
	cairo_ps_surface_set_eps(surface, TRUE);
	cairo_ps_surface_restrict_to_level(surface, CAIRO_PS_LEVEL_2);
	cr=cairo_create(surface);
	draw(plot, cr);
	cairo_surface_show_page(surface);
	cairo_destroy(cr);
	cairo_surface_finish(surface);
	cairo_surface_destroy(surface);
	return FALSE;
}

gboolean plot_linear_print_svg(GtkWidget *plot, gchar* fout)
{
	cairo_t *cr;
	cairo_surface_t *surface;

	surface=cairo_svg_surface_create(fout, (gdouble) (plot->allocation.width), (gdouble) (plot->allocation.height));
	cr=cairo_create(surface);
	draw(plot, cr);
	cairo_destroy(cr);
	cairo_surface_destroy(surface);
	return FALSE;
}