adj_systeim()

[Gary E. Miller]

Yo Eric!

On Sun, 12 Mar 2017 08:43:37 -0400
"Eric S. Raymond" <esr at thyrsus.com> wrote:

> Hal Murray <hmurray at megapathdsl.net>:
> > It may be worth checking ntp classic.  We may have lost something in
> > that area during all the cleanups.  
> 
> Nope.  I am absolutely on top of this. Gary's analysis has gone down a
> fallback path, not the main one which *does* have ns
> precision.

Prove it please.

> What's actually going on here is that there are two functionally
> similar calls, ntp_adjtime() and adjtimex().  The former is sort of
> semi-portable; it's Mills's original spec for advanced timekeeping
> support, more or less, but it's not standardized and various platform
> implementations of it have quirks and extensions.  The most important
> quirk is that some variants support nanosecond precision, others only
> microsecond.

Not a quirk, documented in POSIX 1999.

> The second one is adjtimex().  This is used under Linux to implement
> ntp_adjtime(), but has additional capabilities the former does not.

And if we do not use them they are equivalent.  Right?

> Therefore we actually prefer to use the
> MOD_ names, they're more portable to (e.g.) BSD systems.

Portability is good.

RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
	gem at rellim.com  Tel:+1 541 382 8588

	    Veritas liberabit vos. -- Quid est veritas?
    "If you can’t measure it, you can’t improve it." - Lord Kelvin
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