On Tuesday 23 March 2004 6:55 pm, John Levon wrote:
> On Tue, Mar 23, 2004 at 06:46:12PM +0000, Angus Leeming wrote:
> > Why don't you like
> > while (!finished) {
> > someNonTrivialFunction();
> > if (fl_check_forms() == FL_EVENT) {
> > ...
> > }
> > }
> >
> > (I guess that this is what you call a 'busy loop'?)
>
> I think this is fine (assuming that fl_check_forms() only returns
> when an event has happened).
Dunno about that. Should check.
> Maybe I misunderstood what you wanted to change in Qt. A "busy
> loop" would be one that chewed CPU despite no events arriving.
This is what seems to happen in the Qt-equivalent. We get a
never-ending stream of calls to 'someNonTrivialFunction()' when
everything else is totally quiet.
> > An alternative to this strategy would be to
> > 1. Reap the zombies in the child_handler function
> Isn't this what you described in your last mail which I said was
> fine?
Must be my poor-English day.
The reaping the zombies bit is the same, but I was asking what is the
best strategy to clean up after the children and post the callbacks
to the rest of the code.
Strategy 1 is to modify the main GUI loop, as above.
Strategy 2 is to use a Timeout as we do currently, but use it only to
post the callbacks of these 'reaped_children' rather than, as now,
using it to both reap the zombies AND post the callbacks.
Basically, I'm at a bit of a loss. The reaping-children bit appears to
be optimized as the handler is invoked only when a SIGCHLD event is
emitted. It seems to be a real pity that we can't be similarly
efficient when posting the callbacks.
Angus
