Index: layer.h
===================================================================
--- layer.h	(revision 12344)
+++ layer.h	(revision 12345)
@@ -28,8 +28,6 @@
 #ifndef PCB_LAYER_H
 #define PCB_LAYER_H
 
-/* How deep subcs can be nested */
-#define PCB_MAX_BOUND_LAYER_RECURSION 128
 
 typedef long int pcb_layer_id_t;
 typedef long int pcb_layergrp_id_t;
@@ -268,6 +266,25 @@
 /* Open the attribute editor for a layer */
 void pcb_layer_edit_attrib(pcb_layer_t *layer);
 
+
+/* How deep subcs can be nested */
+#define PCB_MAX_BOUND_LAYER_RECURSION 128
+
+/* Return the real layer, resolving layer bindings. Returns NULL on
+   error (e.g. binding loop) */
+static inline PCB_FUNC_UNUSED pcb_layer_t *pcb_layer_get_real(pcb_layer_t *layer)
+{
+	int rec = 0;
+
+	while(layer->is_bound) {
+		layer = layer->meta.bound.real;
+		rec++;
+		if ((rec > PCB_MAX_BOUND_LAYER_RECURSION) || (layer == NULL))
+			return NULL;
+	}
+	return layer;
+}
+
 /* list of virtual layers: these are generated by the draw code but do not
    have a real layer in the array */
 typedef struct pcb_virt_layer_s {