Go: A new system programing language

[Walter Bright]

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.