On Wednesday, 9 September 2015 at 19:53:55 UTC, ponce wrote:
Oops, posted by mistake.
On Wednesday, 9 September 2015 at 19:48:00 UTC, cym13 wrote:
Hi,
I know C++ and D without being a C++ or D guru (I know way
more about D though). When talking about memory management the
problem of RAII is often mentioned along with the fact that
classes use the GC. I know well the difference between structs
and classes and don't want to talk about the GC here.
It seems to me that just as one can manage his memory in C++
using unique_ptr, shared_ptr and basic RAII we can manage our
memory using Unique, RefCounted and Scoped.
My question is: what is possible in C++ that isn't in D?
C++ only has a D struct equivalent so all destructors are called
deterministically. It's the addition of classes that create the
problems in D.
C++ can also throw by value, something that D can't really do.
C++ objects can be:
- heap-allocated or not
- have deterministic destructors or not
- be polymorphic or not
without much restrictions.
If you find a way to have the equivalent of virtual functions and
dynamic casts for structs, then all our problems are virtually
solved and struct would be all we need.
How come that we are getting memory debates at all on this
matter if we can do the same thing?
Because D has class objects as an addition, and people want to
use them because they need both polymorphism and holding
resources. This is a very common scenario.
Not all objects need a destructor, but when one need to have a
destructor called, this propagates the need for clean-up to its
owner too.
Hence, class objects that need deterministic destruction are very
easy to come by in D programs.
If there are differences is fixing them an option to have
something to show to D detractors?
There was a proposal to stop the GC from calling destructors,
which didn't take.
There was also proposals of RC classes.
