[Python-Dev] time.sleep(-1) behaviour (original) (raw)

Nick Coghlan ncoghlan at gmail.com
Fri Jul 1 14:46:16 CEST 2011

On Fri, Jul 1, 2011 at 10:17 PM, Tim Lesher <tlesher at gmail.com> wrote:

On Thu, Jun 30, 2011 at 15:13, Ulrich Eckhardt <ulrich.eckhardt at dominolaser.com> wrote:

Hi!

This is a request for clarification for the thread "how to call a function for evry 10 seconds" from the user mailinglist/newsgroup.

The gist is this: 1. On Linux/Python 2.6, time.sleep(-1.0) raises an IOError. 2. On MS Windows/Python 2.5 or 2.7 this sleeps forever. It seems that converting this to a 32-bit integer for Sleep() causes an underflow. 3. Is the behaviour under MS Windows acceptable or a bug? On the Windows side, Sleep(-1) as "infinite" is correct and documented: http://msdn.microsoft.com/en-us/library/ms686298(v=vs.85).aspx

For Sleep, yes, but the time.sleep() docs [1] are completely silent on the behaviour of negative sleep values at the Python level. Question 3 isn't "Is there something wrong with Sleep()?", it is "Is there something wrong with the way time.sleep() uses Sleep()?"

My personal preference would be to standardise on ValueError (since the negative sleep value is the real problem), or, failing that, at least raising an exception of some kind.

[1] http://docs.python.org/dev/library/time#time.sleep

Cheers, Nick.

-- Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia

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