Boost logo

Boost :

Subject: Re: [boost] [thread 1.48] Multiple interrupt/timed_join leads to deadlock
From: AntonioM (antomicx_at_[hidden])
Date: 2012-12-06 11:02:14

Hi Vicente,

> [...]
> template<typename TimeDuration>
> bool timed_join(TimeDuration const& rel_time);
> Preconditions:
> the thread is joinable.

could you please, then, summarize what is the correct way of coping with
a single thread structure from multiple threads of execution in boost

Besides locking it for synchronizing access do you think it would
be safe to access the thread methods like this? (Please don't elaborate
on the specific code choices, I put there some almost non-sense code,
just to better illustrate my question)

end_condition = false
while(not end_condition) {
<get the to_be_joined_thread lock>
if (to_be_joined_thread->joinable()) {
result =
  to_be_joined_thread->timed_join(<1 second>);
if (result) {
end_condition = true;
} else {
end_condition = true;

Suppose at the first round it can't join the thread, after 1 second
it times out, it goes back to the beginning and tries again. Between
the lock release and the new lock acquisition another thread runs the
same code and it manages to join the to_be_joined_thread. When the
first thread gets the lock again, what is it going to find with the
joinable() call?
I would expect a joinable() == false, 'cause the thread has been already
joined by someone else. Am I right?


Boost list run by bdawes at, gregod at, cpdaniel at, john at