Re: [boost] re quest for interest in a garbage collection library

Subject: Re: [boost] re quest for interest in a garbage collection library
From: Achilleas Margaritis (axilmar_at_[hidden])
Date: 2009-04-20 12:50:34

Vicente Botet Escriba wrote:
> 
> 
> Achilleas Margaritis-4 wrote:
>> Sid Sacek wrote:
>>>>> It's the lack of a programming model that integrates
>>>>> destructors and peoples' legitimate expectations that they will be
>>>>> called to release non-memory resxources.  What can you say about the
>>>>> non-memory resources owned by a GC'd object that contains, say, a
>>> mutex?
>>>
>>>> Personally, I don't see why resources like mutexes or files should be
>>>> managed like memory. Resources like that are "binary" resources: they
>>>> have two states (locked/unlocked, opened/closed), which is perfectly
>>>> suited for RAII.
>>>
>>> I think the question David was asking is; if a GC object is holding a
>>> mutex that is currently holding a lock, then when does that lock
>>> release, or how does that lock release? The GC may run in the future,
>>> and in the meanwhile, that lock is frozen.
>>>
>> Aren't scoped locks a better way to handle such issues? The big 
>> advantage of C++ is scoped construction/destruction.
>>
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> 
> 
> Hi,
> 
> The user can use already RAII on its application. Suppose that you have a
> RAII class X that is garbage collected (inherits from gc_object<X>) that
> holds a mutex (or a file handle) and lock (open) it on construction and
> unlock (close) on destruction.
> 
> How the following behaves?
> 
> scoped_ptr<X> p(nex X());
> 
> When the unlock (close) function will be called?
> 
> Does it means that classes like X should not inherit from gc_object<X> and
> the user of X must decide whether the new X() must be garbage collected or
> not? 
> 
> What are the criteria X must satisfy to inherit from gc_object<X> without
> any trouble?
> 
> The GC RAII combination rises clearly some issues, and the user must be
> aware of them. The question is, what the GC library can provide to the user
> to make user life easier and safer.
> 
> HTH,
> Vicente
> 
> 

The gc'd objects can be deleted any time, and therefore RAII works on 
gc'd objects as well.