time(9)
NAME
boottime, time_second, time_uptime - system time variables
SYNOPSIS
#include <sys/time.h>
extern struct timeval boottime;
extern struct time_t time_second;
extern struct timeval time_uptime;
DESCRIPTION
The boottime variable holds the system boot time.
- The time_second variable is the system's ``wall time'' clock
- to the second.
- The time_uptime variable is the number of seconds since
- boot.
- The bintime(9), getbintime(9), microtime(9), getmicro
- time(9),
nanotime(9), and getnanotime(9) functions can be used to get - the current
time more accurately and in an atomic manner. Similarly, - the The
binuptime(9), getbinuptime(9), microuptime(9), getmicroup - time(9),
nanouptime(9), and getnanouptime(9) functions can be used to - get the time
elapse since boot more accurately and in an atomic manner. - The boottime
variable may be read and written without special precau - tions.
SEE ALSO
- clock_settime(2), ntp_adjtime(2), settimeofday(2), bin
- time(9),
binuptime(9), getbintime(9), getbinuptime(9), getmicro - time(9),
getmicrouptime(9), getnanotime(9), getnanouptime(9), micro - time(9),
microuptime(9), nanotime(9), nanouptime(9) - Poul-Henning Kamp, "Timecounters: Efficient and precise
- timekeeping in
SMP kernels", Proceedings of EuroBSDCon 2002, Amsterdam, /usr/share/doc/papers/timecounter.ascii.gz. - Marshall Kirk McKusick and George V. Neville-Neil, The
- Design and
Implementation of the FreeBSD Operating System, - Addison-Wesley,
57-61,65-66, July 2004. - BSD September 17, 2004