Hacker News Reader

HNHacker News

Top New Best Ask Show Jobs

Comment by pjmlp | Hacker News Reader

Parent Full thread

pjmlp·

ARC is automatic memory management.

"The Garbage Collection Handbook", chapter 5

http://gchandbook.org/

View on HN

Yup but people love to argue over the small shit. Chris Lattner even refers to ARC as a form of GC.

Different approaches to memory management differ in extent of how much of programmer's job they automate.

Garbage collectors are fully automatic and rarely if ever require to mind anything; automatic RC does almost everything but requires programmer to analyze and annotate some things as 'weak'; manual RC requires a lot more programmer's effort while still technically being "automatic"; and manual memory management means the programmer does everything.

Automatic/manual is a scale, not a boolean yes/no, and the point is that ARC lies on it a bit closer to manual than garbage collectors.

The thing is, ARC is a garbage collection algorithm.

There isn't anything like ARC vs GC, that is layman knowledge and just wrong from CS point of view.

ARC is not an algorithm, it a language-level feature that generates retain/release calls automatically so that the programmer does not have to. Unlike GC systems where the resulting program does run an algorithm (and wastes CPU on that), with ARC the generated program is no different as if retain/release were written manually and runs no extra code.

That is an implementation detail of how a reference counting algorithm can be implemented.

If you're going to say that, then hand-coded memory allocation is just an implementation detail for a garbage collection algorithm.

True in some sense, but mostly useless. Come on.

Reply on news.ycombinator.com