2016-01-27 17:24 GMT+01:00 Sven Barth <pascaldra...@googlemail.com>: > I'll need to look at your code again, but even for class functions the > same rules (and worries) as for normal methods apply. > I hope that your research in Generics.Defaults will be successful for manual interfaces :P
Most important about manual interfaces, and why can't be used any other solution without painful consequences: 1. we don't want to use ARC interfaces (for singletons created at startup in Generics.Defaults) side note: in Generics.Defaults is introduced TSingletonImplementation for non ARC COM interfaces 2. even if point 1. is simple to achieve, it brings a lot of problems because we need to keep somewhere our singletons and that means: SIGSEGV exception is guaranteed, during closing application in many scenarios program X; uses A, B; begin end. A source code: unit A; interface uses Contnrs; var GarbageCollector: Contnrs.TObjectList; implementation initialization GarbageCollector := Contnrs.TObjectList.Create(true); finalization GarbageCollector.Free; end. in B is used A and Generics.Collections. unit B; interface uses A, Generics.Collections; implementation begin GarbageCollector.Add(TDictionary.Create); end. Generics.Collections (which is using Generics.Defaults) and our Generics.Defaults is released before A. It will cause a memory violation in Generics.Defaults for our singleton O__o. To avoid this memory violation is necessary to omit point 1. 3. To avoid memory violation, any instance of collection should be owner of instance of IComparer / IEqualityComparer and that is performance and memory killer in comparison to manual interfaces. -- Best regards, Maciej Izak
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