|
> Anything more complex than the C ABI is what makes people say there is a runtime. But Rust (or Zig, or C++ for that matter) don't use the C ABI, either, except for specifically annotated functions. > In that case, the runtime has already been started, and is being reused. True, but I'm trying to say that the notion of "starting" the runtime (or the GC for that matter) is not really well-defined. HotSpot does need to be "started", but, say, Graal Native Image, which is sort of an AOT-compiled, statically linked JVM, isn't really "started". > Java calling C may add a management layer on Java's side, but C/C++/Rust/Zig/etc need very little (hence, minimal runtime). In some implementations of Java this may be the case in some situations, yes. I would go further and say that that's the typical case, i.e. if you want to embed the stock HotSpot, you will need to call some initialisation functions. If that's what's meant by "runtime", then it's mostly correct, but it's more an implementation detail of HotSpot. Even without it there will remain more important differences between C++/Zig/Rust/C and Java, and this matter of "runtime" is not the most interesting aspect. For example, that Java is usually compiled JIT and Rust is usually compiled AOT is a bigger and more interesting difference. |
Not only that, but Rust, C, Zig also require some setup before their `main()` can start as well.
That is why people say they have a "minimal runtime", rather than "no runtime". There is still a bit of setup there, without which the languages cannot function, or can only function in a limited mode.
Otherwise agreed on all your other points.