New function: list_do(), calls a function on each item in the list.

@@ -44,6 +44,11 @@ extern int list_count    __P ((list_t, size_t *pcount));
 extern int list_remove   __P ((list_t, void *item));
 extern int list_get      __P ((list_t, size_t _index, void **pitem));
 
+typedef int list_action_t __P ((void* item, void* cbdata));
+
+extern int list_do       __P ((list_t list, list_action_t * action, void *cbdata));
+
+
 #ifdef __cplusplus
 }
 #endif

@@ -179,3 +179,21 @@ list_get (list_t list, size_t indx, void **pitem)
   monitor_unlock (list->monitor);
   return status;
 }
+
+int
+list_do (list_t list, list_action_t * action, void *cbdata)
+{
+  struct list_data *current;
+  int status = 0;
+  if (list == NULL || action == NULL)
+    return EINVAL;
+  monitor_rdlock (list->monitor);
+  for (current = list->head.next; current != &(list->head);
+       current = current->next)
+    {
+      if ((status = action (current->item, cbdata)))
+	break;
+    }
+  monitor_unlock (list->monitor);
+  return status;
+}