+/**
+ * tal_del_destructor - remove a destructor callback function.
+ * @ptr: The tal allocated object.
+ * @function: the function to call before it's freed.
+ *
+ * If @function has not been successfully added as a destructor, this returns
+ * false. Note that if we're inside the destructor call itself, this will
+ * return false.
+ */
+#define tal_del_destructor(ptr, function) \
+ tal_del_destructor_((ptr), typesafe_cb(void, void *, (function), (ptr)))
+
+/**
+ * tal_add_destructor2 - add a 2-arg callback function when context is destroyed.
+ * @ptr: The tal allocated object.
+ * @function: the function to call before it's freed.
+ * @arg: the extra argument to the function.
+ *
+ * Sometimes an extra argument is required for a destructor; this
+ * saves the extra argument internally to avoid the caller having to
+ * do an extra allocation.
+ *
+ * Note that this can only fail if your allocfn fails and your errorfn returns.
+ */
+#define tal_add_destructor2(ptr, function, arg) \
+ tal_add_destructor2_((ptr), \
+ typesafe_cb_cast(void (*)(tal_t *, void *), \
+ void (*)(__typeof__(ptr), \
+ __typeof__(arg)), \
+ (function)), \
+ (arg))
+
+/**
+ * tal_del_destructor - remove a destructor callback function.
+ * @ptr: The tal allocated object.
+ * @function: the function to call before it's freed.
+ *
+ * If @function has not been successfully added as a destructor, this returns
+ * false. Note that if we're inside the destructor call itself, this will
+ * return false.
+ */
+#define tal_del_destructor(ptr, function) \
+ tal_del_destructor_((ptr), typesafe_cb(void, void *, (function), (ptr)))
+
+/**
+ * tal_del_destructor2 - remove 2-arg callback function.
+ * @ptr: The tal allocated object.
+ * @function: the function to call before it's freed.
+ * @arg: the extra argument to the function.
+ *
+ * If @function has not been successfully added as a destructor with
+ * @arg, this returns false.
+ */
+#define tal_del_destructor2(ptr, function, arg) \
+ tal_del_destructor2_((ptr), \
+ typesafe_cb_cast(void (*)(tal_t *, void *), \
+ void (*)(__typeof__(ptr), \
+ __typeof__(arg)), \
+ (function)), \
+ (arg))
+enum tal_notify_type {
+ TAL_NOTIFY_FREE = 1,
+ TAL_NOTIFY_STEAL = 2,
+ TAL_NOTIFY_MOVE = 4,
+ TAL_NOTIFY_RESIZE = 8,
+ TAL_NOTIFY_RENAME = 16,
+ TAL_NOTIFY_ADD_CHILD = 32,
+ TAL_NOTIFY_DEL_CHILD = 64,
+ TAL_NOTIFY_ADD_NOTIFIER = 128,
+ TAL_NOTIFY_DEL_NOTIFIER = 256
+};
+
+/**
+ * tal_add_notifier - add a callback function when this context changes.
+ * @ptr: The tal allocated object, or NULL.
+ * @types: Bitwise OR of the types the callback is interested in.
+ * @callback: the function to call.
+ *
+ * Note that this can only fail if your allocfn fails and your errorfn
+ * returns. Also note that notifiers are not reliable in the case
+ * where an allocation fails, as they may be called before any
+ * allocation is actually done.
+ *
+ * TAL_NOTIFY_FREE is called when @ptr is freed, either directly or
+ * because an ancestor is freed: @info is the argument to tal_free().
+ * It is exactly equivalent to a destructor, with more information.
+ * errno is set to the value it was at the call of tal_free().
+ *
+ * TAL_NOTIFY_STEAL is called when @ptr's parent changes: @info is the
+ * new parent.
+ *
+ * TAL_NOTIFY_MOVE is called when @ptr is realloced (via tal_resize)
+ * and moved. In this case, @ptr arg here is the new memory, and
+ * @info is the old pointer.
+ *
+ * TAL_NOTIFY_RESIZE is called when @ptr is realloced via tal_resize:
+ * @info is the new size, in bytes. If the pointer has moved,
+ * TAL_NOTIFY_MOVE callbacks are called first.
+ *
+ * TAL_NOTIFY_ADD_CHILD/TAL_NOTIFY_DEL_CHILD are called when @ptr is
+ * the context for a tal() allocating call, or a direct child is
+ * tal_free()d: @info is the child. Note that TAL_NOTIFY_DEL_CHILD is
+ * not called when this context is tal_free()d: TAL_NOTIFY_FREE is
+ * considered sufficient for that case.
+ *
+ * TAL_NOTIFY_ADD_NOTIFIER/TAL_NOTIFIER_DEL_NOTIFIER are called when a
+ * notifier is added or removed (not for this notifier): @info is the
+ * callback. This is also called for tal_add_destructor and
+ * tal_del_destructor.
+ */
+#define tal_add_notifier(ptr, types, callback) \
+ tal_add_notifier_((ptr), (types), \
+ typesafe_cb_postargs(void, tal_t *, (callback), \
+ (ptr), \
+ enum tal_notify_type, void *))
+
+/**
+ * tal_del_notifier - remove a notifier callback function.
+ * @ptr: The tal allocated object.
+ * @callback: the function to call.
+ */
+#define tal_del_notifier(ptr, callback) \
+ tal_del_notifier_((ptr), \
+ typesafe_cb_postargs(void, void *, (callback), \
+ (ptr), \
+ enum tal_notify_type, void *), \
+ false, NULL)
+