uni20::async::TaskFactoryAwaitable Concept Reference

Concept for awaitables that support shared promise-neutral ownership. More...

#include <async_task_promise.hpp>

Concept definition

template<typename T>
concept uni20::async::TaskFactoryAwaitable =  requires(T a, TaskFactory factory) {
  { a.await_suspend(std::move(factory)) } noexcept -> std::same_as<void>;
  { a.num_awaiters() } -> std::convertible_to<int>;
}

Detailed Description

Concept for awaitables that support shared promise-neutral ownership.

This concept is satisfied if:

• The awaitable provides a num_awaiters() method returning an integer count
• It provides non-throwing await_suspend(TaskFactory)
• The return type of await_suspend is void

Note

This is used by composite awaiters like all(...) that must split ownership across multiple sub-awaitables.

num_awaiters() runs before ownership transfer and need not be noexcept; await_suspend(TaskFactory) runs afterward and must be.