Michiel Borkent Today at 11:40 PM
When I produce a String in a graalvm native library and pass a pointer to it to another language. At what point does that String get garbage collected or freed? So I call free on it myself, and if so, how? (edited)




14 replies

Chris Seaton  5 minutes ago
Do you mean from the C API?

Michiel Borkent  3 minutes ago
So, I'm returning this value: https://github.com/borkdude/sci/blob/e4e860ee343b025514d2de2d7aa0bea097178983/libsci/src/sci/impl/LibSci.java#L15
And I'm using this value from e.g. C++ or Rust. Who cleans it up eventually? (edited)

Chris Seaton  3 minutes ago
Are you familiar with the handles and references in the C API?

Michiel Borkent  3 minutes ago
Here is a C++ program that uses this lib:
https://github.com/borkdude/sci/blob/e4e860ee343b025514d2de2d7aa0bea097178983/libsci/src/from_cpp.cpp#L14 (edited)

Michiel Borkent  2 minutes ago
Is this the C API for GraalVM or the C API in general?

Chris Seaton  2 minutes ago
graal_create_isolate etc

Chris Seaton  2 minutes ago
It has handles and references in that API

Michiel Borkent  1 minute ago
I'm not really familiar with it. I barely got this stuff working by imitating examples. Where's the best place to read up on it?

Chris Seaton  1 minute ago
I'm not massively clear myself, but I know if you returned an object it's alive within the scope of a handle, or reference, scope

Chris Seaton  1 minute ago
It's not well-documented anywhere I can find either

Chris Seaton  1 minute ago
You probably need to dig into the source code yourself

Chris Seaton  < 1 minute ago
Some things I want to do seem to be privileged to the API that the polyglot C API uses.

Chris Seaton  < 1 minute ago
Have you looked at how the Polyglot C API works? It returns string pointers, that may explain it.

Michiel Borkent  < 1 minute ago
I have looked at it a bit after you pointed me to it.