async_binary_semaphore
A async_binary_semaphore is the equivalent of the std::binary_semaphore.
binary_semaphore is an alias for specialization of std::counting_semaphore with LeastMaxValue being 1. Implementations may implement binary_semaphore more efficiently than the default implementation of std::counting_semaphore.
Same description and basic interface as async_counting_semaphore.
- Note:
Semaphores are also often used for the semantics of signalling/notifying rather than mutual exclusion, by initializing the semaphore with 0 and thus blocking the receiver(s) that try to acquire(), until the notifier “signals” by invoking release(n).
For mutual exclusion see async_mutex.
Example
simple_future<void> your_class::get_work();
async_function<>
your_class::do_work(thread_t _thread, async_counting_semaphore<1>& _sem)
{
/* Move into our thread */
co_await yield(_thread);
/* Consumer loop wont block as it suspends... */
while (true) {
/* Process work as it comes in... */
co_await _sem;
/* Do some work... */
}
}
async_function<>
your_class::queue_work()
{
/* Move into thread 0 */
co_await yield(thread_t{0})
async_counting_semaphore<1> sem(engine_, false);
/* Create worker [logical] threads 1 - n */
const auto threads = engine_->number_of_workers();
assert(t > 1);
for (std::uint16_t t = 1; t < threads; ++t) {
do_work(thread_t{t}, sem, work_orders);
}
/* Producer loop wont block as it suspends... */
while (true) {
/* Get work from somewhere */
co_await get_work();
/* notify a thread */
sem.release();
}
}
-
using zab::async_binary_semaphore = async_counting_semaphore<1>
-
template<>
class zab::async_counting_semaphore<1>
