diff -ur a/thr.py b/thr.py
--- a/thr.py	2020-10-29 22:38:06.000000000 +0900
+++ b/thr.py	2020-11-01 00:02:09.000000000 +0900
@@ -90,31 +90,105 @@
 	return empty.to_attr( e, locals() )
 
 
+def stat_lst_new():
+	lst = []
+	lock = lock_new()
+
+	def add(stat):
+		if stat not in lst:
+			lock.on()
+			lst.append( stat )
+			lock.off()
+	def rm(stat):
+		if stat in lst:
+			lock.on()
+			lst.remove( stat )
+			lock.off()
+
+	def gc():
+		for stat in lst[ : ]:
+			stat.gc()
+
+	def quit(tmout=None):
+		for stat in lst[ : ]:
+			stat.quit( tmout )
+
+	return empty.new( locals() )
+
+stat_lst = stat_lst_new()
+
+def stat_new(th):
+	e = empty.new()
+	e.v = None
+	stop_ev = event_new()
+
+	def set(s):
+		e.v = s
+
+	def set_run():
+		set( 'run' )
+		stat_lst.add( e )
+
+	def set_stop():
+		set( 'stop' )
+		stop_ev.set()
+
+	def set_joined():
+		stat_lst.rm( e )
+		set( 'joined' )
+
+	is_stat = lambda s: e.v == s
+	is_run = lambda : is_stat( 'run' )
+	is_stop = lambda : is_stat( 'stop' )
+	wait_stop = lambda tmout=None: stop_ev.wait( tmout )
+
+	def gc():
+		if is_stop():
+			th.join()
+
+	def quit(tmout=None):
+		if is_run():
+			th.quit_ev.set()
+		if wait_stop( tmout ):
+			gc()
+
+	return empty.add( e, locals() )
+
+
 def th_new(target=None, args=(), gc=None):
 	e = empty.new()
 
 	quit_ev = threading.Event()
 	th = None
+	stat = stat_new( e )
 
 	def func(*args):
 		if e.target:
+			stat.set_run()
 			e.target( *e.args )
+			stat.set_stop()
 		if gc:
 			gc.put( e )
 	def start():
+		stat_lst.gc()
 		e.th = threading.Thread( target=func, args=e.args )
 		e.th.daemon = True
 		e.th.start()
 		if gc:
 			gc.lst.add( e )
-	def join():
+	def join(tmout=None):
 		if e.th:
+			if tmout != None:
+				if not stat.wait_stop( tmout ):
+					return  # !
 			e.th.join()
+			stat.set_joined()
 			if gc:
 				gc.lst.rm( e )
-	def stop():
+	def stop(tmout=None):
 		quit_ev.set()
-		join()
+		join( tmout )
+		stat_lst.gc()
 
 	return empty.to_attr( e, locals() )