Re: [Vala] Using uninitialized Glib.TimeVal

[Jonas Kulla <nyocurio gmail com>]

2013/4/14 Alexander Krivács Schrøder <alexschrod gmail com>

> Hi.
>
> I'm trying to use Glib.TimeVal with its from_iso8601() initializer, but
> I can't get the generated C code not to contain a call to
> g_get_current_time() first. At first, I tried this Vala code:
>
> string iso8601_date = "1999-05-31T11:20:00";
> TimeVal time_val;
> time_val.from_iso8601(iso8601_date);
>
> but that makes the compiler complain:
>
> error: use of possibly unassigned local variable `time_val'
>
> So then I tried this code:
>
> string iso8601_date = "1999-05-31T11:20:00";
> TimeVal time_val = TimeVal();
> time_val.from_iso8601(iso8601_date);
>
> but that makes the compiler output the following code:
>
> g_get_current_time (&time_val);
> g_time_val_from_iso8601 (iso8601_date, &time_val);
>
> What do I do to make it not call g_get_current_time()? I know it's
> probably minimal, but it's still wasted CPU cycles and extraneous code
> to compile and whatnot, and I want the option to leave it out if at all
> possible. If it isn't possible, a way to make it possible should be
> considered to be implemented.
>
> Regards,
> Alexander K. Schrøder
>
>
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Hi,

GTimeVal seems a little bit problematic. Ideally, you would want to declare
the "from_iso8601" method as a named constructor to circumvent the default
one (which results in the g_get_current_time), and from a small test I just
did
this works out fine Vala wise. The only problem I see is that this call
returns
a boolean indicating whether the conversion was successful, which would be
lost without any way to find out the result. I guess the way it should
really be
done is to have the default constructor just initialize the struct to zero
and have
the "get_current_time" as a separate method, but for that additional glib
code
would have to exist.

I think your best trade off would be to go with your first suggestion and
ignore
the valac warning. But why is circumventing the get_current_time call so
important to you? Are you running this code in a tight loop?

Jonas