[pebal]

C++ isn't hostile toward garbage collection — it's more the programmers using C++ who are . C++ is the only language that can have an optional, totally pause-less, concurrent GC engine (SGCL). No other programming language, not even Java, offers such a collector.

[pizlonator]

This is false.

Lots of pauseless concurrent GCs have shipped for other languages. SGCL is not special in that regard. Worse, SGCL hasn’t been shown to actually avoid disruptions to program execution while the shipping concurrent GCs for Java and other languages have been shown to really avoid disruptions.

(I say disruptions, not pauses, because avoiding “pauses” where the GC “stops” your threads is only the first step. Once you tackle that you have to fix cases of the GC forcing the program to take bursts of slow paths on pointer access and allocation.)

SGCL is a toy by comparison to other concurrent GCs. For example is has hilariously complex pointer access costs that serious concurrent GCs avoid.

[pebal]

There isn’t a single truly pause-less GC for Java — and I’ve already proven that to you before. If such a GC exists for any other language, name it.

And no, SGCL doesn’t introduce slow paths, because mutators never have to synchronize with the GC. Pointer access is completely normal — unlike in other languages that rely on mechanisms like read barriers.

Poluzuj gumkę, serio.

[gpderetta]

It is hostile in the sense that it allows hiding and masking pointers, so it is hard to have an exact moving GC.

SGCL, as impressive as it is, AFAIK requires pointers to be annotated, which is problematic for memory safety, and I'm not sure that it is a moving GC.

[pebal]

SGCL introduces the `tracked_ptr` smart pointer, which is used similarly to `shared_ptr`. The collector doesn't move data, which makes it highly efficient and — perhaps surprisingly — more cache-friendly than moving GCs.