What libraries need to do GC? That is a language issue and not a library issue. When you are embedding a language like Go in a C program, its runtime becomes

What libraries need to do GC? That is a language issue and not a library issue. When you are embedding a language like Go in a C program, its runtime becomes a library. But that's the example the proves the rule: there are (or were) well-known problems with that. Libraries shouldn't be doing GC.