Garbage collection is analyzing the heap and figuring out what can be collected. Reference counting requires the code to increment or decrement a counter and frees memory when the counter hits zero. They’re fundamentally different approaches. Also reference counting isn’t necessarily automatic, Objective-C had manual reference counting since day one.

[–] BatmanAoD@programming.dev 3 points 3 hours ago

"Garbage collection" is ambiguous, actually; reference counting is traditionally considered a kind of "garbage collection". The type you're thinking of is called "tracing garbage collection," but the term "garbage collection" is often used to specifically mean "tracing garbage collection."

[–] CanadaPlus@lemmy.sdf.org 2 points 5 hours ago

It's still mentioned as one of the main approaches to garbage collection in the garbage collection Wikipedia article.