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ntp_gettime(3) [linux man page]

NTP_GETTIME(3)						     Linux Programmer's Manual						    NTP_GETTIME(3)

NAME
ntp_gettime, ntp_gettimex - get time parameters (NTP daemon interface) SYNOPSIS
#include <sys/timex.h> int ntp_gettime(struct ntptimeval *ntv); int ntp_gettimex(struct ntptimeval *ntv); DESCRIPTION
Both of these APIs return information to the caller via the ntv argument, a structure of the following type: struct ntptimeval { struct timeval time; /* Current time */ long int maxerror; /* Maximum error */ long int esterror; /* Estimated error */ long int tai; /* TAI offset */ /* Further padding bytes allowing for future expansion */ }; The fields of this structure are as follows: time The current time, expressed as a timeval structure: struct timeval { time_t tv_sec; /* Seconds since the Epoch */ suseconds_t tv_usec; /* Microseconds */ }; maxerror Maximum error, in microseconds. This value can be initialized by ntp_adjtime(3), and is increased periodically (on Linux: each sec- ond), but is clamped to an upper limit (the kernel constant NTP_PHASE_MAX, with a value of 16,000). esterror Estimated error, in microseconds. This value can be set via 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. tai TAI (Atomic International Time) offset. ntp_gettime() returns an ntptimeval structure in which the time, maxerror, and esterror fields are filled in. ntp_gettimex() performs the same task as ntp_gettime(), but also returns information in the tai field. RETURN VALUE
The return values for ntp_gettime() and ntp_gettimex() are as for adjtimex(2). Given a correct pointer argument, these functions always succeed. VERSIONS
The ntp_gettime() function is available since glibc 2.1. The ntp_gettimex() function is available since glibc 2.12. ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7). +-------------------------------+---------------+---------+ |Interface | Attribute | Value | +-------------------------------+---------------+---------+ |ntp_gettime(), ntp_gettimex() | Thread safety | MT-Safe | +-------------------------------+---------------+---------+ CONFORMING TO
ntp_gettime() is described in the NTP Kernel Application Program Interface. ntp_gettimex() is a GNU extension. SEE ALSO
adjtimex(2) ntp_adjtime(3), time(7) NTP "Kernel Application Program Interface" <http://www.slac.stanford.edu/comp/unix/package/rtems/src/ssrlApps/ntpNanoclock/api.htm> Linux 2017-09-15 NTP_GETTIME(3)

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NTP_GETTIME(3)						     Linux Programmer's Manual						    NTP_GETTIME(3)

NAME
ntp_gettime, ntp_gettimex - get time parameters (NTP daemon interface) SYNOPSIS
#include <sys/timex.h> int ntp_gettime(struct ntptimeval *ntv); int ntp_gettimex(struct ntptimeval *ntv); DESCRIPTION
Both of these APIs return information to the caller via the ntv argument, a structure of the following type: struct ntptimeval { struct timeval time; /* Current time */ long int maxerror; /* Maximum error */ long int esterror; /* Estimated error */ long int tai; /* TAI offset */ /* Further padding bytes allowing for future expansion */ }; The fields of this structure are as follows: time The current time, expressed as a timeval structure: struct timeval { time_t tv_sec; /* Seconds since the Epoch */ suseconds_t tv_usec; /* Microseconds */ }; maxerror Maximum error, in microseconds. This value can be initialized by ntp_adjtime(3), and is increased periodically (on Linux: each sec- ond), but is clamped to an upper limit (the kernel constant NTP_PHASE_MAX, with a value of 16,000). esterror Estimated error, in microseconds. This value can be set via 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. tai TAI (Atomic International Time) offset. ntp_gettime() returns an ntptimeval structure in which the time, maxerror, and esterror fields are filled in. ntp_gettimex() performs the same task as ntp_gettime(), but also returns information in the tai field. RETURN VALUE
The return values for ntp_gettime() and ntp_gettimex() are as for adjtimex(2). Given a correct pointer argument, these functions always succeed. VERSIONS
The ntp_gettime() function is available since glibc 2.1. The ntp_gettimex() function is available since glibc 2.12. ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7). +-------------------------------+---------------+---------+ |Interface | Attribute | Value | +-------------------------------+---------------+---------+ |ntp_gettime(), ntp_gettimex() | Thread safety | MT-Safe | +-------------------------------+---------------+---------+ CONFORMING TO
ntp_gettime() is described in the NTP Kernel Application Program Interface. ntp_gettimex() is a GNU extension. SEE ALSO
adjtimex(2) ntp_adjtime(3), time(7) NTP "Kernel Application Program Interface" <http://www.slac.stanford.edu/comp/unix/package/rtems/src/ssrlApps/ntpNanoclock/api.htm> COLOPHON
This page is part of release 4.15 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/. Linux 2017-09-15 NTP_GETTIME(3)

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