played with thread syncing

[kunzhutich]

No description provided.

[maksimpustovoyt]

Please address 1 comment and merge

[maksimpustovoyt]

identity

[maksimpustovoyt]

Please address 1 comment and merge
Let's discuss today the strategy

[maksimpustovoyt]

Let's discuss T x, Can it be const T & ? or can it be std::move()

[kunzhutich]

Maksim, I think this implementation is wrong:

while (true) {
    not_full.wait(lock);              // waits even if there's already space
    if (queue.size() < _cap) break;   // only checked *after* waking
}

If add() is called when the queue already has space (queue.size() < _cap), no other thread is required to call not_full.notify_one(). Since condition variables do not queue notifications, this thread can go to sleep with space available and never wake up → potential infinite wait.

Also, according to cppreference.com, any thread that intends to wait on a std::condition_variable must:

1. Check the condition, in case it was already updated and notified.
2. Call wait, wait_for, or wait_until on the std::condition_variable (atomically releases the mutex and suspends thread execution until the condition variable is notified, a timeout expires, or a spurious wakeup occurs, then atomically acquires the mutex before returning).
3. Check the condition and resume waiting if not satisfied.

[maksimpustovoyt]

We already discuss it... the code has race for queue.size()

[maksimpustovoyt]

We already discuss it... the code has race for queue.empty()

[maksimpustovoyt]

We already discuss it... the code has race for queue.size()

[maksimpustovoyt]

We already discuss it... the code has race for queue.empty()