On Sat, Dec 7, 2013 at 11:27 PM, Gustavo Sverzut Barbieri <
barbi...@gmail.com> wrote:
> On Fri, Dec 6, 2013 at 10:19 PM, Carsten Haitzler <ras...@rasterman.com>
> wrote:
> >
> > On Fri, 6 Dec 2013 17:26:21 -0200 Gustavo Sverzut Barbieri <
> barbi...@gmail.com>
> > said:
> >
> > > On Fri, Dec 6, 2013 at 10:42 AM, David Seikel <onef...@gmail.com>
> wrote:
> > > > On Fri, 6 Dec 2013 10:12:09 -0200 Gustavo Sverzut Barbieri
> > > > <barbi...@gmail.com> wrote:
> > > >
> > > >> On Thu, Dec 5, 2013 at 10:23 PM, Daniel Juyung Seo
> > > >> <seojuyu...@gmail.com> wrote:
> > > >> > Dear all, this is Daniel Juyung Seo.
> > > >> >
> > > >> > I propose EFL_SAFE_FREE macro for efl.
> > > >> > It looks like:
> > > >> >
> > > >> > # define EFL_SAFE_FREE(_h, _fn) do { if (_h) { _fn((void*)_h);
> _h
> > > >> > = NULL; } } while (0)
> > > >> >
> > > >> > As I have been using ELM_SAFE_FREE for months, I found out that
> > > >> > this macro is quite useful in terms of code readability, reducing
> > > >> > human mistakes, and using much smaller number of lines with the
> > > >> > same functionality.
> > > >> >
> > > >> > Enlightenment has
> > > >> > # define E_FREE_FUNC(_h, _fn) do { if (_h) { _fn((void*)_h); _h =
> > > >> > NULL; } } while (0)
> > > >> >
> > > >> > Elementary has
> > > >> > #define ELM_SAFE_FREE(_h, _fn) do { if (_h) { _fn((void*)_h); _h =
> > > >> > NULL; } } while (0)
> > > >> >
> > > >> > So why not efl?
> > > >> >
> > > >> > By using EFL_SAFE_FREE, this (Old) code will reborn as a (New)
> code.
> > > >> > 5 lines down to 1 line.
> > > >> > (Old)
> > > >> > if (svr->until_deletion)
> > > >> > {
> > > >> > ecore_timer_del(svr->until_deletion);
> > > >> > svr->until_deletion = NULL;
> > > >> > }
> > > >> >
> > > >> > (New)
> > > >> > EFL_SAFE_FREE(svr->until_deletion, ecore_timer_del);
> > > >>
> > > >> bad name as there is nothing save in it.
> > > >>
> > > >> EINA_FREE_AND_NULL(ptr, freefunc) would be more descriptive, code is
> > > >> the same. Or:
> > > >>
> > > >> EINA_FREE_AND_NULL(ptr) // does free()
> > > >> EINA_DISPOSE_AND_NULL(ptr, disposefunc) // generic version
> > > >>
> > > >> I'm not a native speaker, eventually there is a better name for the
> > > >> second one.
> > > >
> > > > Safe, as in "this is the safe way to do it", nothing to do with
> saving
> > > > things.
> > >
> > > i know, but what is safe in it? Because it checks for null before
> >
>
Hello
> > the "safe" here is that it makes things safe afterwards. you no longer
> have a
> > dangling pointer variable (in case you use it again now you've freed the
> > object).
>
>
Yes. Exactly that is what this macro intended.
As we discussed the same thing, ELM_SAFE_FREE, long ago in the mailing
list, "safe" looks good to me.
> I've mentioned this over an over, while in some places we do want to
> NULL the pointer because it is a valid value indicating something (ie:
> no timer running, no object in use...) many others we do NOT want to
> zero this pointer because the pointer shouldn't be used at all... and
> if we stick a NULL and then check for such special value elsewhere
> we're hiding bugs.
>
>
Sure exactly. I already know that you mentioned this long before in the
mailing list.
As I mentioned in the first mail,this macro is not a silver bullet and
should not be overused.
So use it only when you have to.
And about your suggestion about EINA_FREE_AND_NULL, having this macro in
eina looks good.
How do others think?
EINA_SAFE_FREE!
> Also, if you set a pointer to NULL you lose valgrind tracing. If you
> do not set to NULL you can get it to say that the pointer was freed
> elsewhere and then you can easily trace why your bug happened.
>
>
>
Yes I also remember you mentioned this before in the mailing list.
So we should use this macro only when we really need it.
If there is no objection I will work on EINA_SAFE_FREE.
Thanks.
Daniel Juyung Seo (SeoZ)
>
> --
> Gustavo Sverzut Barbieri
> --------------------------------------
> Mobile: +55 (19) 9225-2202
> Contact: http://www.gustavobarbieri.com.br/contact
>
>
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