Task & Timer GClasses

Async task execution, timers, and counters.

Source: kernel/c/root-linux/src/c_task.c, c_timer.c, c_timer0.c, c_counter.c

C_TASK¶

Task execution engine — orchestrates multi-step jobs with timeout and result handling.

Key attributes¶

C_TIMER¶

High-level timer — recommended for general use. Uses periodic yuno events with millisecond configuration. See the Timer API for helper functions.

Key attributes¶

Notes¶

• Do not call gobj_start() / gobj_stop() directly — use set_timeout(), set_timeout_periodic(), and clear_timeout().

C_TIMER0¶

Low-level timer — uses io_uring directly. Each instance opens a file descriptor. Prefer C_TIMER unless you need lower-level control.

Key attributes¶

Same as C_TIMER.

Notes¶

• Use set_timeout0(), set_timeout_periodic0(), and clear_timeout0().

• Not for a deferral. A timer of one millisecond, armed to continue on the next cycle of the loop, is not a time: it costs an io_uring timeout for something with nothing to wait for, and every continuation then arrives as EV_TIMEOUT, so the machine trace says “timeout” instead of what happened. Use gobj_post_event() for that, and a timer when there is a real time to measure.

• Cleared and armed again in one turn of the loop (a pause and a play): the cancel of the first arm is in flight, and the io_uring timer cannot start until it ends. The new arm is kept and done when the cancel comes back, and that cancel is not published as EV_STOPPED: the timer runs. Up to 7.25.21 the arm failed (“cannot start timer: is CANCELING”) and the timer stayed off.

  PRIVATE int mt_pause(hgobj gobj)
  {
      clear_timeout0(priv->timer);    // the cancel goes out
      return 0;
  }
  PRIVATE int mt_play(hgobj gobj)
  {
      set_timeout_periodic0(priv->timer, priv->timeout);  // kept, done when the cancel ends
      return 0;
  }

  If the gobj is stopped in that same turn (gobj_stop() and an arm), the cancel is a stop after all: EV_STOPPED is said and the arm dropped. Up to 7.25.22 nothing was said.

• A stopped timer never ends the loop. Its callback answers 0 whatever the state of its gobj; the yuno’s loop ends with set_yuno_must_die(). Up to 7.25.22 it answered -1 when its gobj was not running, and yev_loop ends the loop on a -1: a child timer stopped while the yuno ran -- a service stopped alone, clearing and stopping its own timer in mt_stop -- stopped the whole yuno.

  PRIVATE int mt_stop(hgobj gobj)
  {
      clear_timeout0(priv->timer);
      gobj_stop(priv->timer);         // its cancel comes back as EV_STOPPED; the yuno runs on
      return 0;
  }

C_COUNTER¶

Event counter — tracks incoming events until reaching a target count or a timeout, then fires a final event.

Key attributes¶