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INITTODR(9)		 BSD Kernel Developer's Manual		   INITTODR(9)

NAME
     inittodr — initialize system time

SYNOPSIS
     void
     inittodr(time_t base);

DESCRIPTION
     The inittodr() function determines the time and sets the system clock.
     It tries to pick the correct time using a set of heuristics that examine
     the system's battery-backed clock and the time reported by the file sys‐
     tem, as given in base.  Those heuristics include:

     ·	 If the battery-backed clock has a valid time, and is not signifi‐
	 cantly behind the time provided by base, it is used.

     ·	 If the battery-backed clock does not have a valid time, or is signif‐
	 icantly behind the time provided in base, and the time provided in
	 base is within reason, base is used as the current time.

     ·	 If the battery-backed clock appears invalid, and base appears non-
	 sensical or was not provided (was given as zero), an arbitrary base
	 (typically some time within the same year that the kernel was last
	 updated) will be used.

     Once a system time has been determined, it is stored in the time vari‐
     able.

DIAGNOSTICS
     The inittodr() function prints diagnostic messages if it has trouble fig‐
     uring out the system time.	 Conditions that can cause diagnostic messages
     to be printed include:

     ·	 There is no battery-backed clock present on the system.

     ·	 The battery-backed clock's time appears nonsensical.

     ·	 The base time appears nonsensical.

     ·	 The base time and the battery-backed clock's time differ by a large
	 amount.

SEE ALSO
     clock_ymdhms_to_secs(9), resettodr(9), time_second(9)

BUGS
     Some systems use heuristics for picking the correct time that are
     slightly different.

BSD			       September 6, 2006			   BSD

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