GC and dtors ~ a different approach?

[Bruno Medeiros]

kris wrote:
> Bruno Medeiros wrote:
>>
>>
>> All of those pros you mention are valid. But you'd have one serious con:
>> * Any class which required cleanup would have to be manually memory 
>> managed.
>>
> 

Just one addendum: I was just pointing out that con, I wasn't saying it 
was or was not, a bad idea overall.

> 
> First, let's change the verbiage of "valid" and "unspecified" to be 
> "deterministic" and "non-deterministic" respectively (per Don C).
> 

Let's not. *g*  See my reply to the Don.

> 
> To get to your assertion: under the suggested model, any class with 
> resources that need to be released should either be 'delete'd at some 
> appropriate point, or have raii applied to it. Classes with dtors that 
> are not cleaned up in this manner can be treated as "leaks" (and can be 
> identified at runtime).
> 
> Thus, the term "manually memory managed" is not as clear as it might be: 
> raii can be used to clean up, and scope(exit) can be used to cleanup. An 
> explicit 'delete' can be used to cleanup. There's no malloc() or 
> anything like that invoved.
> 

Those are all manual memory management. (Even if auto and scope() are 
much better than plain malloc/free).
[Note: RAII's auto = scope(exit)]
You would have an automatic leak/failure detection, true.

> The truly serious problem with a 'lazy' cleanup is that the dtor will 
> wind up invoked with non-determinstic state (typically leading to a 
> serious error). The other concern with lazy cleanup is what Mike 
> addresses (if the resource needs cleaning up, it should be done in a 
> timely manner ~ not at some arbitrary point in the future).
> 

The state is *undefined*, it is not "non-deterministic" nor 
"deterministic". This is the kind of terminology blur up that I was 
leery of. :P

-- 
Bruno Medeiros - CS/E student
http://www.prowiki.org/wiki4d/wiki.cgi?BrunoMedeiros#D