Python - multithreading / multiprocessing, very strange problem.
Posted
by orokusaki
on Stack Overflow
See other posts from Stack Overflow
or by orokusaki
Published on 2010-04-14T21:12:59Z
Indexed on
2010/04/14
21:13 UTC
Read the original article
Hit count: 609
import uuid
import time
import multiprocessing
def sleep_then_write(content):
time.sleep(5)
print(content)
if __name__ == '__main__':
for i in range(15):
p = multiprocessing.Process(target=sleep_then_write,
args=('Hello World',))
p.start()
print('Ah, what a hard day of threading...')
This script output the following:
Ah, what a hard day of threading...
Ah, what a hard day of threading...
Ah, what a hard day of threading...
Ah, what a hard day of threading...
Ah, what a hard day of threading...
Ah, what a hard day of threading...
Ah, what a hard day of threading...
Ah, what a hard day of threading...
Ah, what a hard day of threading...
AAh, what a hard day of threading..
h, what a hard day of threading...
Ah, what a hard day of threading...
Ah, what a hard day of threading...
Ah, what a hard day of threading...
Ah, what a hard day of threading...
Ah, what a hard day of threading...
Hello World
Hello World
Hello World
Hello World
Hello World
Hello World
Hello World
Hello World
Hello World
Hello World
Hello World
Hello World
Hello World
Hello World
Hello World
Firstly, why the heck did it print the bottom statement sixteen times (one for each process) instead of just the one time?
Second, notice the AAh, and h, about half way down; that was the real output. This makes me wary of using threads ever, now.
(Windows XP, Python 2.6.4, Core 2 Duo)
© Stack Overflow or respective owner
