It would be nice if threading.Thread constructor will have a "daemon"
argument as well.

This way we'll be able to write
    Thread(target=some_function, daemon=1).start()

Instead of currently writing
    t = Thread(target=some_function)
    t.daemon = True
    t.start()

+1

Attaching a patch against trunk (at revision 72805).

I think that 
    self.__daemonic = daemon or self._set_daemon()
is wrong, need to thing about it.

+1, but I can't apply the patch cleanly:

$ patch -p0 < threading.diff
patching file Doc/library/threading.rst
Hunk #1 succeeded at 198 (offset -17 lines).
Hunk #2 succeeded at 211 (offset -17 lines).
Hunk #3 succeeded at 230 (offset -17 lines).
patching file Lib/threading.py
Hunk #1 succeeded at 407 with fuzz 1 (offset -16 lines).
Hunk #2 FAILED at 416.
1 out of 2 hunks FAILED -- saving rejects to file Lib/threading.py.rej
patching file Lib/test/test_threading.py
Hunk #1 succeeded at 350 with fuzz 2 (offset 14 lines).

I'm attaching a new diff (svn diff > threading.diff), hope this one's OK.

Nope.  Our working copies seem to be different.  I'm uploading mine, 
which I just update to revision 73468.  Please diff yours against that 
and against HEAD too, just in case.

Hunk 2 on threading.py fails because your attributes use two leading 
underscores and mine use only one.  I have no idea why hunk4 fails.

I'm diffing against the 2.7 branch, I guess your comes from the 3.2?

Will checkout 3.2 and do it there as well.

Attaching a diff against the py3k branch on revision 73468

> I'm diffing against the 2.7 branch, I guess your comes from the 3.2?
*forehead meets desktop*

Patch applies cleanly and all tests pass.  I used it for a while and 
everything seemed OK.  After someone else tests, I say we go for it :)

+1 to the py3k diff. :)
Hey, I think this daemon property should be set as a keyword argument of
the Thread constructor.

+1 on making it a keyword-only argument.

+1 from me as well.

+1 to this, and I'd need to make the same patch/change to 
multiprocessing.Process as well

Patch for multiprocessing, adding the daemon kwarg attached.