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

NAME
     inittodr - initialize system time

SYNOPSIS
     #include <sys/types.h>
     #include <sys/systm.h>

     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 obtained from the root
     file system, as given in base.  How the base value is obtained will vary
     depending on the root file system type.  The heuristics used include:

     •   If the battery-backed clock has a valid time, it is used.

     •   If the battery-backed clock does not have a valid time, the time
         provided in base will be used.

     Once a system time has been determined, it is stored in the time
     variable.

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

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

SEE ALSO
     resettodr(9), time(9)

BUGS
     On many systems, inittodr() has to convert from a time expressed in terms
     of year, month, day, hours, minutes, and seconds to time, expressed in
     seconds.  Many of the implementations could share code, but do not.

     Each system's heuristics for picking the correct time are slightly
     different.

     The FreeBSD implementation should do a better job of validating the time
     provided in base when the battery-backed clock is unusable.  Currently it
     unconditionally sets the system clock to this value.

FreeBSD 13.1-RELEASE-p6         March 22, 1997         FreeBSD 13.1-RELEASE-p6