On Fri, 04 May 2012 08:38:21 -0400, Benjamin Thaut
<c...@benjamin-thaut.de> wrote:
Am 04.05.2012 14:18, schrieb Steven Schveighoffer:
On Fri, 04 May 2012 02:45:03 -0400, Benjamin Thaut
<c...@benjamin-thaut.de> wrote:
Hi,
I'm currently doing some manual memory management and as the delete
keyword is deperecated I want to replace it with a custom Delete
template. I now need to destroy a array of structs, this however seems
only be possible by using the typeinfo object of the struct and
calling xdtor on that which is a indirect function call for every
struct in the array. I would like to destroy the struct directly with
a direct call to the destructor. This seems not to be possible because
calling __dtor results in calling the wrong dtor (apperently there are
3, __dtor, __fieldDtor, __aggrDtor). So __dtor is the wrong destructor
because it does not destroy any members of the struct but __fieldDtor
and __aggrDtor are not callable. They show up in the
__traits(allMembers) list but if you try to call them you get a error
message that such a property does not exist. So is there any way to
directly destroy a struct, and if not why can't we directly expose the
correct destructor, because apprently it is known at compile time.
Look at what object.clear() does, since it is meant to replace delete.
In fact, I'd advise just using that if you have the type handy.
-Steve
object.clear() useses the typeinfo.destroy() method which is a virtual
function call plus a indirect function call. So thats even one level of
indirection more. Also clear does reinitializle the struct after
destroying it, which is completely unneccesary in my case, because I'm
about to free the memory anyway.
Look at what TypeInfo_Struct.destroy() does:
override void destroy(void* p)
{
if (xdtor)
(*xdtor)(p);
}
So here is what I'd suggest (for an array of struct S):
auto ti = typeid(S).xdtor;
if(xdtor)
foreach(ref s; arr)
(*xdtor)(&s);
Which should be as efficient as possible, given the current
implementation, you don't have to repeat the lookup for each element.
I remember that __dtor does the wrong thing, and I advocated it should do
the same thing as calling xdtor, but it didn't go anywhere.
-Steve
