RAII who?

[Jan Hanselaer]

Thanks for the explanation Daniel en Lutger.

Some new qestions come to my mind. Since now there is the 'scope' attribute, 
the auto attribute only exists for type inference?

I have a background in Java and consequently not used to work with 
destructors. But in D apparently it is used although there is a garbage 
collector.
Are there any (style) rules that say when the scope attribute (and a 
destructor) is needed?
I would expect the garbage collector cleaning up all the resources when an 
object gets out of scope ... So till now I never used a destructor and/or 
the scope attribute.

Jan


"Lutger" <lutger.blijdestijn at gmail.com> schreef in bericht 
news:f2mo2h$22e$1 at digitalmars.com...
> Jan Hanselaer wrote:
>> Hi
>>
>> I'm confused about what's meant with Resource Acquisition Is 
>> Initialisation. Can somebody explain this, especially how it is 
>> accomplished in D?
>> Some questions that  arise in my brain when reading and thinking about 
>> it.
>>
>> - Giving each variable a default value is this part of RAII? Or has it 
>> nothing to do with it?
>> - What's the use of the keyword 'auto' in the whole story?
>> - What's the link with garbage collection?
>> - If I don't use the keyword auto, memory resources are not automatically 
>> freed?
>> - ...
>>
>> I just don't seem to get te whole picture here. But I suspect it's not 
>> that complicated.
>> Anyone with a short and clear definition?
>>
>> Thanks in advance!
>> Jan
>
> According to wikipedia: "The acquisition is bound to the construction 
> (initialization) whereas the release is bound to the automatic, 
> deterministic destruction (uninitialization) of the variable. Since a 
> destructor of an automatic variable is called when leaving its scope, it 
> can be guaranteed that the resource is released as soon as the variable's 
> life time ends."
>
> Thus, if we are talking about memory as a resource, this usually means for 
> every new in the constructor a delete in the destructor. The link with 
> garbage collection is that it is an alternative technique often used in 
> C++, to make it easier and safer to manage memory. Less so in D, since 
> there is the garbage collector.
>
> Auto used to be what scope classes are now. In D, contrary to C++, 
> destructors are not automatically called upon scope exit. With scope 
> classses they are, so these are more useful for RAII, for example file 
> handles.