python threading t.join () 方法
学习python线程部分发现t1.join()这个方法，书上讲 "t.join(timeout)等待直到线程终止或者出现超时为止，timeout为浮点数，线程......."
按照书上的理解t1.join()应该是等待线程的结束，而从我的试验结果来看似乎t1.join()在等待线程结束后直接令整个进程都终止了。
附上代码：
1 from threading import Thread
2 import time
3
4 def test1 ( times, sec, yy ):
5 print str(times) + ' ' + str(sec) + ' ' + yy
6 for i in range ( times ):
7 print '%d111111111111111' % i
8 time.sleep (1)
9
10 def test2 ( times ):
11 print times
12 for i in range ( times ):
13 print '%d22222222222222222222222222' % i
14 time.sleep ( 1)
15
16
17 t1 = Thread ( target = test1, name = 'teTTTTTTTTTTTTTTTTTTTTTst1', args = (20,30), kwargs = {'yy':'345'} )
18 t2 = Thread ( target = test2, name = 'teRRRRRRRRRRRRRRRRRRRRRst2', args = (5,) )
19
20 t1.daemon = True
21 t2.daemon = True
22
23 t1.start ()
24 #t1.join ( 4.0 )
25
26 print t1.name
27 t2.start ()
28 t2.join ( ) <<<<<<<<<<<<<<<<<<<<在这里等待t2线程结束
29
30 print t2.name
运行结果：
20 30 345teTTTTTTTTTTTTTTTTTTTTTst1
5
022222222222222222222222222
0111111111111111
122222222222222222222222222
1111111111111111
222222222222222222222222222
2111111111111111
3111111111111111
322222222222222222222222222
4111111111111111
422222222222222222222222222
teRRRRRRRRRRRRRRRRRRRRRst25111111111111111
结果是t2运行结束后t1也不能执行......困惑中，求解.....
[解决办法]
主线程A启动了子线程B，调用b.setDaemaon(True)，则主线程结束时，会把子线程B也杀死，与C/C++中得默认效果是一样的。
daemon
A boolean value indicating whether this thread is a daemon thread (True) or not (False). This must be set before start() is called, otherwise RuntimeError is raised. Its initial value is inherited from the creating thread; the main thread is not a daemon thread and therefore all threads created in the main thread default to daemon = False.
The entire Python program exits when no alive non-daemon threads are left.
