Kirk McDonald Wrote:

> However, there's a very important detail which you should not overlook: You are passing a pointer to GC-controlled data to a C library. The D garbage collector doesn't scan the C library for references, so you will need to keep a reference to any structs you pass to Carbon in your D code. Otherwise, the GC will feel free to collect them when you least expect it. This can be done with an AA:

Yes, thank you, I was aware of that. As it turns out, there's other stuff I need to do with my delegate that I can't do (namely, treat the .ptr portion of it as a pointer to a class derived from some interface Foo), so I ended up having to create a little class wrapper.

I add the class to the GC's root with std.gc.addRoot(). This should work, right (rather than storing it in an AA)?

Rick Mann wrote:
> Kirk McDonald Wrote:
> 
>> However, there's a very important detail which you should not overlook: You are passing a pointer to GC-controlled data to a C library. The D garbage collector doesn't scan the C library for references, so you will need to keep a reference to any structs you pass to Carbon in your D code. Otherwise, the GC will feel free to collect them when you least expect it. This can be done with an AA:
> 
> Yes, thank you, I was aware of that. As it turns out, there's other stuff I need to do with my delegate that I can't do (namely, treat the .ptr portion of it as a pointer to a class derived from some interface Foo), so I ended up having to create a little class wrapper.
> 
> I add the class to the GC's root with std.gc.addRoot(). This should work, right (rather than storing it in an AA)?

That's going to tie you to a particular gc implementation, though.  So I think the practice should be avoided unless you have a compelling reason to do it that way.

--bb