System Primitives¶
This section covers two core helpers used in user code:
- sleep_for — suspend a coroutine for a given duration.
- co_spawn — schedule a coroutine into the global task queue.
sleep_for¶
Namespace: usub::uvent::system::this_coroutine
template <typename Rep, typename Period>
task::Awaitable<void> sleep_for(const std::chrono::duration<Rep, Period>& duration);
Usage:
using namespace std::chrono_literals;
task::Awaitable<void> worker() {
// suspend coroutine for 1 second
co_await system::this_coroutine::sleep_for(1s);
// resume here after timeout
}
What happens internally:
- A
Timerobject is created and registered in theTimerWheel. - The currently running coroutine handle is stored in the timer.
- When the timer expires, the coroutine is resumed.
This is the standard way to do coroutine-friendly sleeping instead of std::this_thread::sleep_for.
co_spawn¶
Namespace: usub::uvent::system
Usage:
task::Awaitable<void> client_handler() {
// ...
}
int main() {
// put coroutine into the global task queue
system::co_spawn(client_handler());
usub::Uvent loop(4);
loop.run();
}
What happens internally:
- Extracts the coroutine’s promise via
get_promise(). - Enqueues its handle into the global shared task queue (
SharedTasks). - From there the event loop picks it up and starts execution.
This is the entry point for scheduling coroutines in uvent — any coroutine you want to run must be launched with co_spawn.
Timers¶
Timers in uvent are managed by a hierarchical TimerWheel with minimal overhead.
You can either use high-level helpers like sleep_for, or schedule custom timers directly.
spawn_timer¶
/**
* @brief Schedules a timer in timer wheel.
*
* Adds the given timer instance into timer wheel handler,
* allowing it to be triggered after its configured expiry.
*
* @param timer Pointer to a valid timer object.
*
* @note If the timer type is set to TIMEOUT, it will fire once;
* otherwise, it will repeat indefinitely.
*
* @warning This method does not check whether the timer is initialized
* or already active. Use only with properly constructed and inactive timers.
*/
inline void spawn_timer(utils::Timer* timer);