On 10/24/2013 07:58 AM, Rene Zwanenburg wrote:
I'm writing a D wrapper for a C library. I was planning to use
RefCounted structs to control the lifetime of objects created by this
library. Please check the following example:
http://dpaste.dzfl.pl/b49962bf
Foo would be an opaque struct. createFoo() and destroyFoo() would be
implemented in the C library (I know I have to declare them extern(C),
this is just an example).
As you can see, that code prints 'Destroying Foo' twice, with different
pointers. I expected destroyFoo to be called only once, on the instance
created by createFoo(), when the Bar instance goes out of scope. Current
behaviour causes an invalid pointer to be passed to destroyFoo(). Is
this a bug in RefCounted or am I doing something wrong?
Technically, it is a problem with FooWrapper. Regardless of whether
RefCounted's behavior, by default, structs in D are freely copyable and
movable value types. The compiler can do those things as it sees fit.
Since FooWrapper owns a resource, it must also define the post-blit to
make a copy of Foo.
(As an aside, dmd at git head does not make such a copy.)
Ali
