[Python-Dev] PEP 418 is too divisive and confusing and should be postponed (original) (raw)

PJ Eby pje at telecommunity.com
Thu Apr 5 18:41:46 CEST 2012

On Wed, Apr 4, 2012 at 11:41 PM, Cameron Simpson <cs at zip.com.au> wrote:

On 04Apr2012 22:23, PJ Eby <pje at telecommunity.com> wrote: | On Apr 4, 2012 7:28 PM, "Victor Stinner" <victor.stinner at gmail.com> wrote: | > More details why it's hard to define such function and why I dropped | > it from the PEP. | > | > If someone wants to propose again such function ("monotonic or | > fallback to system" clock), two issues should be solved: | > | > - name of the function | > - description of the function | | Maybe I missed it, but did anyone ever give a reason why the fallback | couldn't be to Steven D'Aprano's monotonic wrapper algorithm over the | system clock? (Given a suitable minimum delta.) That function appeared to | me to provide a sufficiently monotonic clock for timeout purposes, if | nothing else.

It was pointed out (by Nick Coglan I think?) that if the system clock stepped backwards then a timeout would be extended by at least that long. For example, code that waited (by polling the synthetic clock) for 1s could easily wait an hour if the system clock stepped back that far. Probaby undesirable.

Steven D'Aprano's algorithm doesn't do that. If the system clock steps backwards, it still stepped forward by a specified minimum delta. The amount of time that a timeout was extended would be a function of the polling frequency, not the presence of absence of backward steps in the underlying clock. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.python.org/pipermail/python-dev/attachments/20120405/36362f26/attachment.html>

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