On Tuesday, 15 May 2012 at 12:36:30 UTC, Dmitry Olshansky wrote:
On 15.05.2012 16:27, Ondrej Pokorny wrote:
On Tuesday, 15 May 2012 at 09:44:08 UTC, Jonathan M Davis
wrote:
On Tuesday, May 15, 2012 11:26:49 Namespace wrote:
On Tuesday, 15 May 2012 at 09:23:51 UTC, Kagamin wrote:
> Difference with what?
> new is a safe feature: it allocates in the GC heap
That's what i mean. So i have to delete it yourself with
"delete
arr;", or not?
No. _Never_ use delete. It's going to be deprecated. The GC
worries about
freeing memory allocated on the GC heap, and new always
allocates on
the GC
heap. If you don't want to allocate on the GC heap, then use
malloc
and free,
in which case you _do_ need worry about freeing the memory.
If you need to force destruction before the GC collects an
object, you
can
call clear on that object to have its destructor called and
its vtbl
zeroed
out, but it's memory still isn't freed. That's the GC's job.
If you really have to, you can use core.memory to manipulate
the GC heap
(including calling GC.free), but you really shouldn't be
messing with
any of
that unless you really need to and you know what you're doing.
- Jonathan M Davis
Hi,
does this hold for structs too?
struct H
{
this(int a){writeln("ctor");}
~this(){writeln("dtor");}
};
...
H* h = new H(5);
clear(h);
...
output:
ctor
seems like destructor is not called.
if I change declaration of H to class H. output is following:
ctor
dtor
I tried to create object according to RAII idiom and in case
of struct H
my file handle remained open and I was still able to write to
file...
Ondrej
I thought in C++ RAII is about (i.e. even in C++ no heap
allocation):
H h = H(5);
Same works in D. A call to clear in you code above doesn't
call destructor, it only zeros out pointer.
If you absolutely need pointers & heap and yet manual memory
managment use:
clear(*h);
Explanation:
clear(x) calls x.__dtor if x is struct or class, then assigns
x = T.init;
A better way might be to just check if x.__dtor is callbale
(thus pointer to sstruct will also work).
I don't need this stuff I am playing with language and wonder
why. Originally I had there auto h = H(5); and after changing H
to struct I did not realized why that happened.
Thanks a lot for explanation, now it makes perfect sense, but I
have still little bit unpleasant felling about it because of
behavior of ref to classes vs pointers to structs with clear.
Both are dynamically allocated data, so I was expecting same
response from clear(x).
Ondrej
