threading.Thread documentation can be improved

[roysmith]

BPO	11073
Nosy	@rhettinger, @pitrou, @bitdancer, @briancurtin

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2011-01-31.14:40:18.494>
created_at = <Date 2011-01-31.01:42:50.737>
labels = ['type-feature', 'docs']
title = 'threading.Thread documentation can be improved'
updated_at = <Date 2011-01-31.14:40:18.492>
user = 'https://bugs.python.org/roysmith'

bugs.python.org fields:

activity = <Date 2011-01-31.14:40:18.492>
actor = 'pitrou'
assignee = 'docs@python'
closed = True
closed_date = <Date 2011-01-31.14:40:18.494>
closer = 'pitrou'
components = ['Documentation']
creation = <Date 2011-01-31.01:42:50.737>
creator = 'roysmith'
dependencies = []
files = []
hgrepos = []
issue_num = 11073
keywords = []
message_count = 8.0
messages = ['127566', '127568', '127569', '127581', '127583', '127597', '127600', '127601']
nosy_count = 6.0
nosy_names = ['rhettinger', 'roysmith', 'pitrou', 'r.david.murray', 'brian.curtin', 'docs@python']
pr_nums = []
priority = 'normal'
resolution = 'works for me'
stage = None
status = 'closed'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue11073'
versions = ['Python 3.1', 'Python 2.7', 'Python 3.2']

[roysmith]

The documentation for the threading.Thread constructor says:

"target is the callable object to be invoked by the run() method. Defaults to None, meaning nothing is called."

This could be improved by explicitly stating that target is called in a static context. As written, it takes a bit of thought (and experimentation) to be sure of that.

[bitdancer]

I have no idea what "a static context" means, so it wouldn't make it any clearer to me. Can you explain further what your confusion is?

[roysmith]

What I meant was whether target should be declared as @staticmethod or not.

[bitdancer]

I still don't understand. I haven't used threading much, but I don't believe I've ever used a static method with it.

[rhettinger]

Roy, it's not clear what you're after. What is it that you think is special about the way the target is called?

[roysmith]

Here's the code I ended up writing:

class Foo():
   def __init__(self):
       self.thread = Thread(target=Foo.runner, args=[self])
       self.thread.start()

   @staticmethod
   def runner(self):
      # blah, blah, blah

It was not immediately clear from the documentation if my runner() method should be declared static or not. In retrospect, it must be (since this can be used with target functions which are not class methods at all), but it took a bit of thought to get from what the documentation said (i.e. 'callable object to be invoked by the run() method') to that conclusion.

It seems to me the documentation could be a bit more explicit that your target does not get called as a method of some object. Changing the text to read, "static function or other callable object" would remove any such confusion.

It could be that some of my confusion is due to my previously working with a C++ threading package where the thread runner functions *were* class methods. Still, it seems like the potential for other people to be similarly confused exists and a little tweaking of the documentation text would help.

[briancurtin]

It was not immediately clear from the documentation if my runner() method should be declared static or not.

The doc doesn't mention static methods at all, and my uses and others that I've seen have never used static methods.

[pitrou]

You don't have to use any staticmethod here (actually, staticmethod is an anti-pattern in Python). Just write:

class Foo():
   def __init__(self):
       self.thread = Thread(target=self.runner)
       self.thread.start()

   def runner(self):
      # blah, blah, blah