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SubjectHow to use CLOCK_REALTIME_ALARM
Hi!

Since alarmtimers have been mainlined there are now 2 new clock id's,
CLOCK_REALTIME_ALARM and CLOCK_BOOTTIME_ALARM which are supposed to wake
up a machine from suspend too. It's roughly outlined here:

http://lwn.net/Articles/429925/

Now me residing in userspace wonder how to use those. It's the first
time I try to use a kernel interface and it is quite possible the
problem is on my end but I have no clue what might be wrong. Here is
some barely working code:

#include <stdio.h>
#include <signal.h>
#include <stdlib.h>
#include <sys/types.h>
#include <time.h>

void
func()
{
printf("pong.\n");
}

int
main(int argc, char *argv[])
{
timer_t id;

struct itimerspec A;
struct sigevent se;

int rc; /* return code */

se.sigev_notify = SIGEV_THREAD;
se.sigev_notify_function = func;
se.sigev_notify_attributes = NULL;

/* doesn't accept CLOCK_REALTIME_ALARM */
rc = timer_create(CLOCK_REALTIME, &se, &id);
printf("%d\n",rc);

/* the only place that seems to actually accept it */
clock_gettime(CLOCK_REALTIME_ALARM, &A.it_value);

A.it_value.tv_sec += 10;

A.it_interval.tv_sec = 0;
A.it_interval.tv_nsec = 0;

/* set timer */
rc = timer_settime(&id, TIMER_ABSTIME, &A, 0);
printf("%d\n",rc);

printf("ping.\n");

/* bad. bad. bad. */
while(1);

return 0;
}

I'd appreciate if someone could point me on what I'm doing wrong or tell
me if the new clock id's work at all.

please CC answers. thanks in advance.


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