Re: about destroy and delete.

[Dsby via Digitalmars-d]

On Wednesday, 20 April 2016 at 09:00:41 UTC, Daniel Kozak wrote:

On Wednesday, 20 April 2016 at 08:10:15 UTC, Dsby wrote:

I see https://dlang.org/deprecate.html#delete
...
so, I want to know why don't destroy direct printf ?


if you call destroy on struct pointer it is same as assign null 
to it

so
destroy(s) is same as s = null;

OK it is more like

s = (Struct*).init;

But if you do (*s).destroy(), it will work (ok it will call 
destructor two times but thats not error)


Or if you use class instead of struct it will works as you 
expected


Thanks for all.

Re: about destroy and delete.

[Marco Leise via Digitalmars-d]

The semantics of `delete` from C++ are pretty clear. It is
meant for dynamically allocated memory. destroy(…) however is
a generic tool that brings the thing you pass in back to an
initial state. For pointers, null is assigned, for structs and
classes (which are not pointers but references) the dtor is
called.
Making it do the same thing for an argument of struct type T
and T* should not be done lightly. It will break generic
code, where the location that calls destroy(…) does not own
the pointed-to struct.

-- 
Marco

Re: about destroy and delete.

[Lass Safin via Digitalmars-d]

On Wednesday, 20 April 2016 at 08:10:15 UTC, Dsby wrote:

I see https://dlang.org/deprecate.html#delete
The delete will be removeed,  when will be deprecate?

and i test destroy/GC.free and delte in struct, the value is 
difference;


struct Struct
{
string value = "struct";
~this()
{
writeln(value);
}
}

void main()
{

auto s = new Struct();
delete s;

writeln("");

}

will printf :
struct


But in
void main()
{

auto s = new Struct();
s.destroy;
GC.free(s);

writeln("");

}

will printf :

struct

If I only GC.free(s); only printf: 

so, I want to know why don't destroy direct printf ?


This is according to the reference, however this behavior should 
probably be changed to match that of the class, which will call 
the destructor immediately.

Re: about destroy and delete.

[Daniel Kozak via Digitalmars-d]

On Wednesday, 20 April 2016 at 08:10:15 UTC, Dsby wrote:

I see https://dlang.org/deprecate.html#delete
...
so, I want to know why don't destroy direct printf ?


if you call destroy on struct pointer it is same as assign null 
to it

so
destroy(s) is same as s = null;

OK it is more like

s = (Struct*).init;

But if you do (*s).destroy(), it will work (ok it will call 
destructor two times but thats not error)


Or if you use class instead of struct it will works as you 
expected

Re: about destroy and delete.

[Dsby via Digitalmars-d]

And ,will destroy mark the memory in GC to be free?