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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-24 04:52:22 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-24 04:52:22 +0000 |
commit | 3d08cd331c1adcf0d917392f7e527b3f00511748 (patch) | |
tree | 312f0d1e1632f48862f044b8bb87e602dcffb5f9 /man/man3/ntp_gettime.3 | |
parent | Adding debian version 6.7-2. (diff) | |
download | manpages-3d08cd331c1adcf0d917392f7e527b3f00511748.tar.xz manpages-3d08cd331c1adcf0d917392f7e527b3f00511748.zip |
Merging upstream version 6.8.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'man/man3/ntp_gettime.3')
-rw-r--r-- | man/man3/ntp_gettime.3 | 135 |
1 files changed, 135 insertions, 0 deletions
diff --git a/man/man3/ntp_gettime.3 b/man/man3/ntp_gettime.3 new file mode 100644 index 0000000..96ac817 --- /dev/null +++ b/man/man3/ntp_gettime.3 @@ -0,0 +1,135 @@ +'\" t +.\" Copyright (c) 2016 by Michael Kerrisk <mtk.manpages@gmail.com> +.\" +.\" SPDX-License-Identifier: Linux-man-pages-copyleft +.\" +.TH ntp_gettime 3 2024-05-02 "Linux man-pages (unreleased)" +.SH NAME +ntp_gettime, ntp_gettimex \- get time parameters (NTP daemon interface) +.SH LIBRARY +Standard C library +.RI ( libc ", " \-lc ) +.SH SYNOPSIS +.nf +.B #include <sys/timex.h> +.P +.BI "int ntp_gettime(struct ntptimeval *" ntv ); +.BI "int ntp_gettimex(struct ntptimeval *" ntv ); +.fi +.SH DESCRIPTION +Both of these APIs return information to the caller via the +.I ntv +argument, a structure of the following type: +.P +.in +4n +.EX +struct ntptimeval { + struct timeval time; /* Current time */ + long maxerror; /* Maximum error */ + long esterror; /* Estimated error */ + long tai; /* TAI offset */ +\& + /* Further padding bytes allowing for future expansion */ +}; +.EE +.in +.P +The fields of this structure are as follows: +.TP +.I time +The current time, expressed as a +.I timeval +structure: +.IP +.in +4n +.EX +struct timeval { + time_t tv_sec; /* Seconds since the Epoch */ + suseconds_t tv_usec; /* Microseconds */ +}; +.EE +.in +.TP +.I maxerror +Maximum error, in microseconds. +This value can be initialized by +.BR ntp_adjtime (3), +and is increased periodically (on Linux: each second), +but is clamped to an upper limit (the kernel constant +.BR NTP_PHASE_MAX , +with a value of 16,000). +.TP +.I esterror +Estimated error, in microseconds. +This value can be set via +.BR ntp_adjtime (3) +to contain an estimate of the difference between the system clock +and the true time. +This value is not used inside the kernel. +.TP +.I tai +TAI (Atomic International Time) offset. +.P +.BR ntp_gettime () +returns an +.I ntptimeval +structure in which the +.IR time , +.IR maxerror , +and +.I esterror +fields are filled in. +.P +.BR ntp_gettimex () +performs the same task as +.BR ntp_gettime (), +but also returns information in the +.I tai +field. +.SH RETURN VALUE +The return values for +.BR ntp_gettime () +and +.BR ntp_gettimex () +are as for +.BR adjtimex (2). +Given a correct pointer argument, these functions always succeed. +.\" FIXME . the info page incorrectly describes the return values. +.SH ATTRIBUTES +For an explanation of the terms used in this section, see +.BR attributes (7). +.TS +allbox; +lbx lb lb +l l l. +Interface Attribute Value +T{ +.na +.nh +.BR ntp_gettime (), +.BR ntp_gettimex () +T} Thread safety MT-Safe +.TE +.SH STANDARDS +.TP +.BR ntp_gettime () +NTP Kernel Application Program Interface. +.TP +.BR ntp_gettimex () +GNU. +.SH HISTORY +.TP +.BR ntp_gettime () +glibc 2.1. +.TP +.BR ntp_gettimex () +glibc 2.12. +.SH SEE ALSO +.BR adjtimex (2), +.BR ntp_adjtime (3), +.BR time (7) +.P +.ad l +.UR http://www.slac.stanford.edu/comp/unix/\:package/\:rtems/\:src/\:ssrlApps/\:ntpNanoclock/\:api.htm +NTP "Kernel Application Program Interface" +.UE |