In Python for *nix, does time.sleep() block the thread or the process?
7 Answers
It blocks the thread. If you look in Modules/timemodule.c in the Python source, you'll see that in the call to floatsleep(), the substantive part of the sleep operation is wrapped in a Py_BEGIN_ALLOW_THREADS and Py_END_ALLOW_THREADS block, allowing other threads to continue to execute while the current one sleeps. You can also test this with a simple python program:
import time
from threading import Thread
class worker(Thread):
def run(self):
for x in xrange(0,11):
print x
time.sleep(1)
class waiter(Thread):
def run(self):
for x in xrange(100,103):
print x
time.sleep(5)
def run():
worker().start()
waiter().start()
Which will print:
>>> thread_test.run()
0
100
>>> 1
2
3
4
5
101
6
7
8
9
10
102
It will just sleep the thread except in the case where your application has only a single thread, in which case it will sleep the thread and effectively the process as well.
The python documentation on sleep() doesn't specify this however, so I can certainly understand the confusion!
Just the thread.
The thread will block, but the process is still alive.
In a single threaded application, this means everything is blocked while you sleep. In a multithreaded application, only the thread you explicitly 'sleep' will block and the other threads still run within the process.
Only the thread unless your process has a single thread.
Process is not runnable by itself. In regard to execution, process is just a container for threads. Meaning you can't pause the process at all. It is simply not applicable to process.
it blocks a thread if it is executed in the same thread not if it is executed from the main code
