Index: trunk/src/attrib.c
===================================================================
--- trunk/src/attrib.c	(revision 27935)
+++ trunk/src/attrib.c	(revision 27936)
@@ -59,9 +59,10 @@
 	/* Replace an existing attribute if there is a name match. */
 	for (i = 0; i < list->Number; i++) {
 		if (strcmp(name, list->List[i].name) == 0) {
-			free(list->List[i].value);
+			char *old_value = list->List[i].value;
 			list->List[i].value = pcb_strdup_null(value);
 			NOTIFY(list, list->List[i].name, list->List[i].value);
+			free(old_value);
 			return 1;
 		}
 	}
@@ -146,9 +147,10 @@
 		if (strcmp(name, dst->List[i].name) == 0) {
 			dst->List[i].cpb_written = 1;
 			if (strcmp(value, dst->List[i].value) != 0) {
-				free(dst->List[i].value);
+				char *old_value = dst->List[i].value;
 				dst->List[i].value = pcb_strdup(value);
 				NOTIFY(dst, dst->List[i].name, dst->List[i].value);
+				free(old_value);
 			}
 			return;
 		}
Index: trunk/src/attrib.h
===================================================================
--- trunk/src/attrib.h	(revision 27935)
+++ trunk/src/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