Two interfaces provide timestamps. gettimeofday(3C) provides the current time in a timeval structure, representing the time in seconds and microseconds since midnight, Greenwich Mean Time, on January 1, 1970. clock_gettime, with a clockid of CLOCK_REALTIME, provides the current time in a timespec structure, representing in seconds and nanoseconds the same time interval returned by gettimeofday(3C).
SunOS uses a hardware periodic timer. For some workstations, the hardware periodic timer is the sole source of timing information. If the hardware periodic timer is the sole source of timing information, the accuracy of timestamps is limited to the timer's resolution. For other platforms, a timer register with a resolution of one microsecond means that timestamps are accurate to one microsecond.