Andrej Mitrovic wrote:
>I'm don't understand why this code calls the dtor before it calls the
>ctor:
>
>import std.stdio;
>import std.typecons;
>
>void main()
>{
> auto wrap1 = Wrapper(1);
>}
>
>void free(ref int _payload)
>{
> writeln("dealloc");
> _payload = 0;
>}
>
>struct Wrapper
>{
> struct Payload
> {
> int _payload;
> this(int h) { writeln("alloc"); _payload = h; }
> ~this() { free(_payload); }
>
> this(this) { assert(false); }
> void opAssign(Wrapper.Payload rhs) { assert(false); }
> }
>
> private alias RefCounted!(Payload, RefCountedAutoInitialize.no)
> Data; private Data _data;
>
> this(int h) { _data = Data(h); }
>}
>
>prints:
>dealloc
>alloc
>dealloc
>
>What's with the first dtor call?
Strange, I can confirm this behavior and it seems to happen all the
time when using RefCounted.
I guess this was never an issue for the RefCounted code in phobos (for
example std.container.Array) as RefCounted was only used to manage
memory, not handles from C libraries. free simply does nothing if
called with a null pointer, so this problem never showed up.
As a workaround, check your handle against null in the destructor
before calling the function to close the handle.
--
Johannes Pfau
