Index: attrib.h
===================================================================
--- attrib.h	(revision 27935)
+++ attrib.h	(revision 27936)
@@ -42,7 +42,7 @@
 struct pcb_attribute_list_s {
 	int Number, Max;
 	pcb_attribute_t *List;
-	void (*post_change)(pcb_attribute_list_t *list, const char *name, const char *value); /* called after put or remove, but not after free(); value is NULL if removed */
+	void (*post_change)(pcb_attribute_list_t *list, const char *name, const char *value); /* called after put or remove, but not after free(); value is NULL if removed; old value is free'd only after the call so cached old values are valid */
 };
 
 /* Returns NULL if the name isn't found, else the value for that named