Multiple access to one object and deallocation

Multiple access to one object and deallocation

[Harry Tucker]

My question is how to count references to an object so it will be 
deallocated only after all references have gone out of scope or set to 
null? An object reference could exist in several lists at any one time.

What I'm looking for is an easy way to catch my own coding errors so I 
don't bleed memory too much by overlooking a reference (access type).

Does anyone know if A# uses managed code? Since that would solve the 
issue through garbage collection. And then is pragma Controlled (ARM 
13.11.3) implemented to prevent automatic garbage collection/movement of 
an object if needed.

Harry
(When totally bored, 49, and retired, fight back! Writing a new mud in 
Ada just might do the trick.)

Re: Multiple access to one object and deallocation

[Marius Amado Alves]

On Wed, 2003-11-05 at 13:17, Harry Tucker wrote:
> My question is how to count references to an object so it will be 
> deallocated only after all references have gone out of scope or set to 
> null? An object reference could exist in several lists at any one time.

This is often called "smart pointers" and often effected with storage
pools. There are examples out there.

Re: Multiple access to one object and deallocation

[Dmitry A. Kazakov]

On Wed, 05 Nov 2003 07:17:39 -0600, Harry Tucker
<snagaghash@sonetcom.com> wrote:

>My question is how to count references to an object so it will be 
>deallocated only after all references have gone out of scope or set to 
>null? An object reference could exist in several lists at any one time.

If "out of scope" means that the access type gets out and if the
target type is controlled, then all allocated objects for which
Unchecked_Deallocation was not called will be destroyed (AARM 7.6.1).

If "out of scope" means an access object, then you need something like
smart pointers. For example:

http://www.dmitry-kazakov.de/ada/components.htm

>What I'm looking for is an easy way to catch my own coding errors so I 
>don't bleed memory too much by overlooking a reference (access type).

Well, let me put it so: reference counting eliminates some errors by
introducing new errors. (:-))

---
Regards,
Dmitry Kazakov
www.dmitry-kazakov.de

Re: Multiple access to one object and deallocation

[Preben Randhol]

On 2003-11-05, Harry Tucker <snagaghash@sonetcom.com> wrote:
> My question is how to count references to an object so it will be 
> deallocated only after all references have gone out of scope or set to 
> null? An object reference could exist in several lists at any one time.

See: http://www.adapower.com/alg/smartp.html


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