The code below sets up a simple timer with SIGEV_THREAD. I compiled the
code as "g++ timertest.cc -o timertest -lrt -pthread".
Running it on my G5 with 2.6.27 (but with an older glibc), it prints:
Creating timer
Setting timer 268509264 for 5-second expiration...
and then the timer never expires. I have an old Fedora Core 4 x86
machine and there it works as expected.
Is there some hard requirement to upgrade glibc? If not, then this
looks like a bug somewhere.
Thanks,
Chris
int main(void)
{
timer_t timer_id;
struct itimerspec its;
struct sigevent se;
// set timer signal event
se.sigev_notify = SIGEV_THREAD;
se.sigev_value.sival_ptr = &timer_id;
se.sigev_notify_function = handler;
se.sigev_notify_attributes = NULL;
if ( timer_create(CLOCK_REALTIME, &se, &timer_id) < 0)
{
printf("create timer failed\n");
fflush(0);
return 0;
}
// set timer.
its.it_value.tv_sec = 1;
its.it_value.tv_nsec = 0;
its.it_interval.tv_sec = 1;
its.it_interval.tv_nsec = 0;
if ( timer_settime(timer_id, 0, &its, NULL) < 0)
{
printf("set timer failed\n");
fflush(0);
return 0;
}
printf("set timer OK\n");
fflush(0);
while(1)
{ pause();}
return 0;
}
Chris Friesen wrote:
> The code below sets up a simple timer with SIGEV_THREAD. I compiled the
> code as "g++ timertest.cc -o timertest -lrt -pthread".
>
> Running it on my G5 with 2.6.27 (but with an older glibc), it prints:
>
> Creating timer
> Setting timer 268509264 for 5-second expiration...
>
> and then the timer never expires. I have an old Fedora Core 4 x86
> machine and there it works as expected.
>
> Is there some hard requirement to upgrade glibc? If not, then this
> looks like a bug somewhere.
I'm getting suspicious of either glibc or my version of strace, as it
shows the child thread calling rt_sigtimedwait() with an empty signal set.
clone(Process 2663 attached
child_stack=0xf7ffe6c0,
flags=CLONE_VM|CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|CLONE_SYSVSEM|CLONE_SETTLS|CLONE_PARENT_SETTID|CLONE_CHILD_CLEARTID|CLONE_DETACHED,
parent_tidptr=0xf7ffeb68, tls=0xf8005f80, child_tidptr=0xf7ffeb68) = 2663
[pid 2662] futex(0xf5f11a4, FUTEX_WAKE, 2147483647) = 0
[pid 2662] timer_create(0, {0x10011050, 32, SIGEV_THREAD_ID, {2663}},
{(nil)}) = 0
[pid 2662] timer_settime(0, , {it_interval={1, 0}, it_value={1, 0}},
<unfinished ...>
[pid 2663] rt_sigprocmask(SIG_BLOCK, [RTMIN], <unfinished ...>
[pid 2662] <... timer_settime resumed> NULL) = 0
[pid 2662] fstat64(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 0),
...}) = 0
[pid 2663] <... rt_sigprocmask resumed> NULL, 8) = 0
[pid 2662] mmap(NULL, 4096, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_ANONYMOUS, -1, 0 <unfinished ...>
[pid 2663] rt_sigtimedwait([], <unfinished ...>
[pid 2662] <... mmap resumed> ) = 0xf7ffa000
[pid 2662] write(1, "set timer OK\n", 13set timer OK
Chris
Chris Friesen wrote:
> I'm getting suspicious of either glibc or my version of strace, as it
> shows the child thread calling rt_sigtimedwait() with an empty signal set.
Looks like glibc was the culprit. It works fine with a newer version.
Sorry for the false alarm.
Chris