I've also seen GC reliant concurrent algorithms that would require a lot more synchronization to keep track of when to actually free an object. GCed languages

I've also seen GC reliant concurrent algorithms that would require a lot more synchronization to keep track of when to actually free an object. GCed languages can just forget about the object and rely on the GC later to figure out what threads have access to valid objects. C and C++ need to figure out if it's safe to free.