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Re: Add sleep builtin

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On 8/25/2018 3:16 PM, Bob Proulx wrote:
> Greg Wooledge wrote:
>   
>> If true, that would actually violate POSIX.
>> You might be remembering it wrong.
Naw...just the marginalia that Bob mentions...
>
> I also remember that at one time the Unix sleep was implemented by
> polling a second granularity clock register.  If one was not lucky
> then polling just before the second turned, and then just after, would
> cause sleep to exit because the second had changed.  A 1 second sleep
> was 0-1 seconds. 
>
> And certainly any using the fractional second extension is past any
> need to worry about the problem.  Because any such system with the
> problem would only handle to a granularity of integer seconds anyway.
>   
---
    I'd hope such would be the case, but as soon as I'd expect such
sane behavior, I'd run into a more simplistic implementation that
met the letter if not intent of some requirement...so such things
tend to stick in my head as possible, though not very useful
implementations.

    I certainly would not take the ever-changing POSIX spec as
a guide to what actually exists or is implemented in the field.
POSIX moved away from their original mission statement of being
"descriptive" to one that is "prescriptive" a long time ago,
with "prescriptive" being based on the wants and desires of
its current membership with little or no regard for usability
or compatibility.

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Re: Add sleep builtin L A Walsh <bash@tlinx.org> - 2018-08-27 10:57 -0700

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