[PATCH 2/2 v3] adjtimex.2: add explanation on ADJ_TAI mode

[PATCH 2/2 v3] adjtimex.2: add explanation on ADJ_TAI mode

[Laurent Georget]

This patch includes the adjtimex mode ADJ_TAI, intended to update the
TAI offset. There are other FIXMEs in the man page and it's a bit
outdated. I'll be on it once those first patches are accepted (to be
sure to do the right thing).

Thanks

Laurent

diff --git a/man2/adjtimex.2 b/man2/adjtimex.2
index 0b919c5..396b8cc 100644
--- a/man2/adjtimex.2
+++ b/man2/adjtimex.2
@@ -24,9 +24,7 @@
 .\" Modified 1997-01-31 by Eric S. Raymond <esr@thyrsus.com>
 .\" Modified 1997-07-30 by Paul Slootman <paul@wurtel.demon.nl>
 .\" Modified 2004-05-27 by Michael Kerrisk <mtk.manpages@gmail.com>
-.\"
-.\" FIXME Document ADJ_TAI (added in Linux 2.6.26)
-.\"		commit 153b5d054ac2d98ea0d86504884326b6777f683d
+.\" Modified 2014-11-30 by Laurent Georget <laurent.georget@supelec.fr>
 .\"
 .\" FIXME Document ADJ_MICRO and ADJ_NANO (added in Linux 2.6.26)
 .\"		commit eea83d896e318bda54be2d2770d2c5d6668d11db
@@ -101,6 +99,7 @@ combination of zero or more of the following bits:
 #define ADJ_ESTERROR          0x0008 /* estimated time error */
 #define ADJ_STATUS            0x0010 /* clock status */
 #define ADJ_TIMECONST         0x0020 /* pll time constant */
+#define ADJ_TAI               0x0080 /* TAI offset */
 #define ADJ_TICK              0x4000 /* tick value */
 #define ADJ_OFFSET_SINGLESHOT 0x8001 /* old-fashioned adjtime() */
 .fi
@@ -110,6 +109,24 @@ Ordinary users are restricted to a zero value for
 .IR modes .
 Only the superuser may set any parameters.
 .br
+In the case of
+.BR ADJ_TAI ,
+as
+.I buf->tai
+is read-only, the new value is passed through
+.IR buf->constant ,
+therefore
+.B ADJ_TIMECONST
+and
+.B ADJ_TAI
+should probably not be used at the same time.
+.PP
+Support for TAI (Atomic International Time, for a complete explanation
about
+what it is and what is the difference between TAI and UTC, see
+.UR http://www.bipm.org/en/bipm/tai/tai.html
+.I BIPM
+.UE )
+has been added in version 2.6.26.
 .ne 12v
 .SH RETURN VALUE
 On success,

Re: [PATCH 2/2 v3] adjtimex.2: add explanation on ADJ_TAI mode

[Michael Kerrisk (man-pages)]

Hello Laurent,

On 11/30/2014 11:14 AM, Laurent Georget wrote:
> This patch includes the adjtimex mode ADJ_TAI, intended to update the
> TAI offset. 

Thanks. Applied, with a few rewordings (which you can find in Git).
One point/question below.

> There are other FIXMEs in the man page and it's a bit
> outdated. I'll be on it once those first patches are accepted (to be
> sure to do the right thing).

I would be happy to get more such patches.

> diff --git a/man2/adjtimex.2 b/man2/adjtimex.2
> index 0b919c5..396b8cc 100644
> --- a/man2/adjtimex.2
> +++ b/man2/adjtimex.2
> @@ -24,9 +24,7 @@
>  .\" Modified 1997-01-31 by Eric S. Raymond <esr-4uCgticg2UFBDgjK7y7TUQ@public.gmane.org>
>  .\" Modified 1997-07-30 by Paul Slootman <paul-pqePwCal/LhZiXb3D+6dPA@public.gmane.org>
>  .\" Modified 2004-05-27 by Michael Kerrisk <mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> -.\"
> -.\" FIXME Document ADJ_TAI (added in Linux 2.6.26)
> -.\"		commit 153b5d054ac2d98ea0d86504884326b6777f683d
> +.\" Modified 2014-11-30 by Laurent Georget <laurent.georget-vbcOdlJ0SulGWvitb5QawA@public.gmane.org>
>  .\"
>  .\" FIXME Document ADJ_MICRO and ADJ_NANO (added in Linux 2.6.26)
>  .\"		commit eea83d896e318bda54be2d2770d2c5d6668d11db
> @@ -101,6 +99,7 @@ combination of zero or more of the following bits:
>  #define ADJ_ESTERROR          0x0008 /* estimated time error */
>  #define ADJ_STATUS            0x0010 /* clock status */
>  #define ADJ_TIMECONST         0x0020 /* pll time constant */
> +#define ADJ_TAI               0x0080 /* TAI offset */
>  #define ADJ_TICK              0x4000 /* tick value */
>  #define ADJ_OFFSET_SINGLESHOT 0x8001 /* old-fashioned adjtime() */
>  .fi
> @@ -110,6 +109,24 @@ Ordinary users are restricted to a zero value for
>  .IR modes .
>  Only the superuser may set any parameters.
>  .br
> +In the case of
> +.BR ADJ_TAI ,
> +as
> +.I buf->tai
> +is read-only, the new value is passed through
> +.IR buf->constant ,
> +therefore
> +.B ADJ_TIMECONST
> +and
> +.B ADJ_TAI
> +should probably not be used at the same time.

"should probably not" seems a little weak to me. Surely it is rather the
case that they *must not* be used at the same time. I changed it to "must not".

Thanks,

Michael


-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
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