Andrei Alexandrescu wrote:
Sean Kelly wrote:
== Quote from Andrei Alexandrescu (seewebsiteforem...@erdani.org)'s
article
dsimcha wrote:
== Quote from Andrei Alexandrescu (seewebsiteforem...@erdani.org)'s
article
It is a bad idea because distinguishing between release of (expensive)
resources from dangerous memory recycling is the correct way to obtain
deterministic resource management within the confines of safety.
This is based on two faulty assumptions:
1. Memory is cheap. (Not if you are working with absurd amounts of
data).
2. Garbage collection is never a major bottleneck. (Sometimes it's
a worthwhile
tradeoff to add a few manual delete statements to code and sacrifice
some safety
for making the GC run less often.)
malloc.
So for placement construction of a class, I guess it would look
something like:
auto x = cast(MyClass) malloc(MyClass.classinfo.init.length);
x.__ctor( a, b, c ); // construct
...
x.__dtor();
free( cast(void*) x );
Is that right?
Yes, I think so, but I haven't checked all the details. For example I'm
not sure whether __ctor copies .init over the memory before running the
user-defined constructor, or expects that to have been done already.
Apparently it doesn't:
http://www.digitalmars.com/techtips/class_objects.html
See, it's even documented.
Anyway, does your statement mean that _ctor is officially supported (by
all conform D compilers)?
Because, quoting from the page above:
"This technique goes "under the hood" of how D works, and as such it is
not guaranteed to work with every D compiler. In particular, how the
constructors and destructors are called is not necessarilly portable."
