From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on ip-172-31-74-118.ec2.internal X-Spam-Level: X-Spam-Status: No, score=-1.9 required=3.0 tests=BAYES_00 autolearn=ham autolearn_force=no version=3.4.6 Path: eternal-september.org!reader02.eternal-september.org!aioe.org!x6YkKUCkj2qHLwbKnVEeag.user.46.165.242.91.POSTED!not-for-mail From: "Dmitry A. Kazakov" Newsgroups: comp.lang.ada Subject: Re: On absurdity of collections 7.6.1 (11.1/3) Date: Thu, 30 Sep 2021 10:06:21 +0200 Organization: Aioe.org NNTP Server Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Injection-Info: gioia.aioe.org; logging-data="26282"; posting-host="x6YkKUCkj2qHLwbKnVEeag.user.gioia.aioe.org"; mail-complaints-to="abuse@aioe.org"; User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.14.0 Content-Language: en-US X-Notice: Filtered by postfilter v. 0.9.2 Xref: reader02.eternal-september.org comp.lang.ada:62883 List-Id: On 2021-09-30 02:23, Randy Brukardt wrote: > It's surely wrong, because you have to deallocate from the same pool as you > allocated. And you have no way to save such a thing. There is no capability > in Ada to use multiple pools with one access type. You mean Unchecked_Dellocation? Maybe, then it is another language bug. However, the object collection schema is irrelevant for a while. The first problem is that Finalize is called twice. > At best, you could directly call Allocate and Deallocate for this purpose, > but it is impossible to use anything built-in. Actually it is possible using a fake pool: type Fake_Pool is new Root_Storage_Pool with record Pool : access Root_Storage_Pool'Class; end record; Allocate goes like this: procedure Allocate ( Pool : in out Fake_Pool; Storage_Address : out System.Address; Size : Storage_Count; Alignment : Storage_Count ) is begin Pool.Pool.Allocate (Storage_Address, Size, Alignment); end Allocate; Then: Fake : Fake_Pool; type Ptr is access Item; for Ptr'Storage_Pool use Fake; -- "collection" lives here function New_Item ( Pool : in out Root_Storage_Pool'Class; Text : String ) return Item_Ptr is Object : Ptr; begin Fake.Pool := Pool'Unchecked_Access; -- Add mutex here Object := new Item (Text'Length); Object.Text := Text; return Object.all'Unchecked_Access; end New_Item; Now the object is intact. -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de