rtc_read(3D)rtc_read(3D)NAME
rtc_read, rtc_resolution - Query the Real-Time Clock
C SYNOPSIS
#include <sys/types.h>
#include <sys/ddi.h>
__int64_t rtc_read(void);
int rtc_resolution(void);
DESCRIPTION
SGI Origin, Octane, and Challenge series systems have a high resolution
monotonically increasing Real-Time Clock (RTC). Software access to this
counter is made available to drivers through rtc_read() and
rtc_resolution().
rtc_read() returns the current value of the counter. The counter is
synchronized across the system and can be used for high resolution time
stamps. It can also be used to calculate timer expiration times for
clock_prtimeout(3D).
rtc_resolution() returns the resolution of the clock on the system in
units of nanoseconds. For example, SGI Origin2000 series systems have an
RTC resolution of 800ns per RTC tick, and so rtc_resolution() will return
a value of 800. SGI Octane systems have a resolution of 80ns / tick and
SGI Challenge series systems have a resolution of 21ns / tick. SGI
Origin3000 series systems have a default but modifiable resolution of
800ns / tick.
SEE ALSOclock_prtimeout(3D), timers(5).
Page 1
