Mike Hearn wrote:
Mixing D's gc world with manually managed memory isn't hard, as
long as the following rules are followed:
1. don't allocate in one language and expect to free in another 2.
keep a 'root' to all gc allocated data in the D side of the fence
(otherwise it may get collected)
Yes it's the second that's the tough part. For instance consider the
case of passing a callback (delegate) to the RPC system written in
c++. How do you keep the associated data rooted without causing
leaks? You'd need to remember to manually add it to the gc roots when
the callback object is created and then unroot them when it's
invoked. So this needs some kind of glue/binding system.
I'm not saying it's impossible or even hard. Just that I've seen such
things done before and they were non-trivial.
Most of the time, nothing needs to be done because the reference is on
the parameter stack that calls the C function.
For the callback object, manually adding/removing the root (there are
calls to the gc to do this) shouldn't be any more onerous than manually
managing memory for it, which is done in C/C++ anyway.
