November 24, 2008 MICROTIME 9

### NAME

bintime, getbintime, microtime, getmicrotime, nanotime, getnanotime - get the current time

### SYNOPSIS

```void` bintime(`` ```struct bintime *bt` )
```void` getbintime(`` ```struct bintime *bt` )
```void` microtime(`` ```struct timeval *tv` )
```void` getmicrotime(`` ```struct timeval *tv` )
```void` nanotime(`` ```struct timespec *ts` )
```void` getnanotime(`` ```struct timespec *tsp` )

### DESCRIPTION

The bintime(``) and getbintime(``) functions store the system time as a at the addresses specified by ```bt`. The microtime(``) and getmicrotime(``) functions perform the same utility, but record the time as a instead. Similarly the nanotime(``) and getnanotime(``) functions store the time as a

The bintime(``), microtime(``), and nanotime(``) functions always query the timecounter to return the current time as precisely as possible. Whereas getbintime(``), getmicrotime(``), and getnanotime(``) functions are abstractions which return a less precise, but faster to obtain, time.

The intent of the getbintime(``), getmicrotime(``), and getnanotime(``) functions is to enforce the user's preference for timer accuracy versus execution time. They should be used where a precision of 1/HZ (e.g., 10 msec on a 100HZ machine, see hz(9)) is acceptable or where performance is priority.

The system realtime clock is guaranteed to be monotonically increasing at all times. As such, all calls to these functions are guaranteed to return a system time greater than or equal to the system time returned in any previous calls.

### SEE ALSO

settimeofday(2), binuptime(9), getbinuptime(9), getmicrouptime(9), getnanouptime(9), hardclock(9), hz(9), inittodr(9), microuptime(9), nanouptime(9), time_second(9), timecounter(9), tvtohz(9)

### CODE REFERENCES

The implementation of the microtime(``) family of functions is in ```sys/kern/kern_tc.c` as a part of the timecounter(9) framework.

The implementation of the time counter sources used by the timecounter(9) is machine dependent, hence its location in the source code tree varies from architecture to architecture.

### AUTHORS

This manual page was written by Jeremy Cooper
and Kelly Yancey <kbyanc@posi.net>
.

### BUGS

Despite the guarantee that the system realtime clock will always be monotonically increasing, it is always possible for the system clock to be manually reset by the system administrator to any date.