On Wednesday, 26 August 2015 at 01:09:15 UTC, ZombineDev wrote:
On Tuesday, 25 August 2015 at 22:35:57 UTC, Jim Hewes wrote:
Although C++ can be ugly, one reason I keep going back to it
rather then commit more time to reference-based languages like
C# is because I like deterministic destruction so much. My
question is whether D can REALLY handle this or not. I've not
been sure about this for some time so now I'm just going to
come out and finally ask.
I know about this RAII section in the documentation:
http://dlang.org/cpptod.html#raii
But I don't believe that handles all cases, such as having
classes as member variables of other classes. (Do the members
get destructors called too?)
Then there is std.typecons.Unique and
std.typecons.RefCounted. With these, can I really get
deterministic destruction for all cases like I would in C++?
If so, it might be a good idea to emphasize this more in the
documentation because I'd think people coming from C++ would
be looking for this.
Jim
Structs in D behave like in C++ - they are created on the stack
(unless you use new or malloc), passed by value and are
automatically destroyed at the end of the scope. All their
members are destroyed recursively after the user defined
destructor is called.
Just try it out in a toy program and see if it works as you
expect.
Classes on the other hand are reference types and are created on
the garbage-collected heap by default (though you can do your own
memory management). Similarly, structs created by new are also
allocated on the GC heap. During collections the GC will call
destructors, but it is not guaranteed and you should not rely on
it. For example (depending on your GC usage and configuration)
only a single collection may occur at the end of the program.
