Re: nonexistent clocks

[Jan Stary <hans%stare.cz@localhost>]

Hi,

> According to tests/lib/libc/sys/t_clock_gettime.c
> ""These clocks aren't supported but are documented"
> 	    " in clock_gettime(2) for some reason"

thanks for the pointer. I am new to NetBSD
and am only getting into tests(7) so please bare with me.

According to these test results (random google hit, but a recent run)

https://www.netbsd.org/~martin/landisk-atf/last_atf.html#lib_libc_sys_t_clock_gettime_clock_getres

calling clock_getres() on these two clocks is expected to fail.
It seems a bit silly to test that NetBSD does _not_ support a clock.
(Isn't clock_gettime() also expected to fail, if they do not exist? :-)
Wouldn't it make more sense to just remove these from the documentation?

> There's also a PR in about CLOCK_MONOTONIC & what it actually represents:
> https://gnats.netbsd.org/60315

Thank you. I am in fact studying the clock_*() interface on various
unixes and what clocks they provide - see my naive take below.

I guess my first question (please excuse the naivety) is where is
NetBSD's clock_get*() implemented? That must be these, right?

/usr/src/sys/kern/kern_time.c:clock_getres1()
/usr/src/sys/kern/subr_time.c:clock_gettime1()

These only support

  CLOCK_REALTIME
  CLOCK_MONOTONIC
  CLOCK_PROCESS_CPUTIME_ID
  CLOCK_THREAD_CPUTIME_ID

and set EINVAL otherwise.

	Jan


#include <stdint.h>
#include <string.h>
#include <stdio.h>
#include <time.h>
#include <err.h>

void
show(clockid_t id, char* name)
{
	struct timespec ts;
	struct timespec cr;
	if (clock_gettime(id, &ts) == -1)
		err(1, NULL);
	if (clock_getres(id, &cr) == -1)
		err(1, NULL);
	printf("%s %10lld.%09ld s, %8ld ns resolution\n",
		name, ts.tv_sec, ts.tv_nsec, cr.tv_nsec);
}

int
main(void)
{
#ifdef  __APPLE__
	show(CLOCK_REALTIME,		"real time");
	show(CLOCK_MONOTONIC,		"monotonic");
	show(CLOCK_UPTIME_RAW,		"up time  ");
	show(CLOCK_PROCESS_CPUTIME_ID,	"proc time");
#elif __OpenBSD__
	show(CLOCK_REALTIME,		"real time");
	show(CLOCK_MONOTONIC,		"monotonic");
	show(CLOCK_BOOTTIME,		"boot time");
	show(CLOCK_UPTIME,		"up time  ");
	show(CLOCK_PROCESS_CPUTIME_ID,	"proc time");
#elif __FreeBSD__
	show(CLOCK_REALTIME,		"real time");
	show(CLOCK_MONOTONIC,		"monotonic");
	show(CLOCK_BOOTTIME,		"boot time");
	show(CLOCK_UPTIME,		"up time  ");
	show(CLOCK_PROCESS_CPUTIME_ID,  "proc time");
#elif __NetBSD__
	show(CLOCK_REALTIME,		"real time");
	show(CLOCK_MONOTONIC,		"monotonic");
	show(CLOCK_PROCESS_CPUTIME_ID,  "proc time");
#else
	show(CLOCK_REALTIME,		"real time");
	show(CLOCK_MONOTONIC,		"monotonic");
	show(CLOCK_BOOTTIME,		"boot time");
	show(CLOCK_PROCESS_CPUTIME_ID,	"proc time");
#endif
	return 0;
}