Thank you for your reply, I get it now.

In other case such as I showed above, it seems we needn't do like the
following ?

if (ev->timer_set) {
ngx_del_timer(ev);
}

2016-09-17 10:48 GMT+08:00 Maxim Dounin <mdounin@mdounin.ru>:

> Hello!
>
> On Sat, Sep 17, 2016 at 08:25:54AM +0800, 洪志道 wrote:
>
> [...]
>
> > static void
> > ngx_http_log_flush(ngx_open_file_t *file, ngx_log_t *log)
> > {
> > ...
> > if (buffer->event && buffer->event->timer_set) {
> > ngx_del_timer(buffer->event);
> > }
> > }
> >
> >
> > I find there are two functions explicitly call event handler.
> > 1. ngx_event_cancel_timers happened as long as worker process quits.
> > 2. ngx_event_expire_timers in ngx_process_events_and_timers.
> >
> > And they remove timer from timer rbtree, then set timer_set zero.
> > After that they call event->handler.
> >
> > So why we call ngx_del_timer in ngx_http_log_flush again?
>
> The ngx_http_log_flush() function is also used as a flush handler
> for the log file, notably called while reopening logs. In this
> case the timer can be set when ngx_http_log_flush() is called and
> should be deleted - and this is what the code in question does.
>
> --
> Maxim Dounin
> http://nginx.org/
>
> _______________________________________________
> nginx-devel mailing list
> nginx-devel@nginx.org
> http://mailman.nginx.org/mailman/listinfo/nginx-devel
_______________________________________________
nginx-devel mailing list
nginx-devel@nginx.org
http://mailman.nginx.org/mailman/listinfo/nginx-devel