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How to reset the clock in Linux adjtimex?
-R, –reset. Reset clock status after setting a clock parameter. For early Linux kernels, using the adjtimex(2) system call to set any time parameter the kernel think the clock is synchronized with an external time source, so it sets the kernel variable time_status to TIME_OK.
What do you need to know about adjtimex in Linux?
Under Linux, the CAP_SYS_TIME capability is required. None of these interfaces is described in POSIX.1 adjtimex () and clock_adjtime () are Linux-specific and should not be used in programs intended to be portable. The preferred API for the NTP daemon is ntp_adjtime ().
Do you have to log in as root for adjtimex?
ASIDES You will have to log in as root for most of the following. The standard kernel will leave the RTC alone only until one of the time parameters is set (using adjtimex, for example).
How does adjtimex update the Timex structure?
It takes a pointer to a timex structure, updates kernel parameters from (selected) field values, and returns the same structure updated with the current kernel values.
How to set the time in the Linux kernel?
Informative Output. For early Linux kernels, using the adjtimex (2) system call to set any time parameter the kernel think the clock is synchronized with an external time source, so it sets the kernel variable time_status to TIME_OK. Thereafter, at 11 minute intervals, it will adjust the CMOS clock to match.
Is there an alternative to adjtimex ( 8 )?
A crude alternative to adjtimex (8) is to have chron run clock (8) or hwclock (8) periodically to sync the system time to the (corrected) RTC. This was recommended in the clock (8) man page, and it works if you do it often enough that you don’t cause large “jumps” in the system time, but adjtimex (8) is a more elegant solution.
How to adjust NTP clock rate with adjtimex?
If you use ADJ_OFFSET_SINGLESHOT, adjtimex () behaves as adjtime (), and you can only use the .offset field. Depending on the size and sign of the adjustment, the NTP clock is speeded up or slowed down for a short while, until the desired offset is achieved; then the NTP clock rate is reverted back to original.