This function is intended for implementing threading.
Normal applications should use
pthread_cond_timedwait(3)
together with
pthread_cond_broadcast(3)
for typical safe suspension with cooperation of the thread
being suspended, or
pthread_suspend_np(3)
and
pthread_resume_np(3)
in some specific situations, instead.
Passing the thread identifier of the calling thread
(
see
thr_self(2)
)
to
thr_wake()
sets a thread's flag to cause the next signal-interruptible sleep
of that thread in the kernel to fail immediately with the
EINTR
error.
The flag is cleared by an interruptible sleep attempt or by a call to
thr_suspend(2).
This is used by the system threading library to implement cancellation.
If
id
is not equal to the current thread identifier, the specified thread is
woken up if suspended by the
thr_suspend
system call.
If the thread is not suspended at the time of the
thr_wake
call, the wake is remembered and the next attempt of the thread to
suspend itself with the
thr_suspend(2)
results in immediate return with success.
Only one wake is remembered.
