How to extract data from native -fwasm-exceptions?

[donalffons]

Hi!
Over at OpenCascade.js, we're using Embind and we're having a simple test case that currently tests -fexceptions support like this:

it("Can catch exceptions", async () => {
  try {
    new module.BRepPrimAPI_MakeCone_1(1, 0.5, 0);
  } catch (e) {
    expect(module.OCJS.getStandard_FailureData(e).GetMessageString()).toBe("cone with negative or null height");
  }
});

The line module.OCJS.getStandard_FailureData(e).GetMessageString() performs more or less what's suggested in the docs on debugging: In this case its dereferencing and casting the pointer into its native type Standard_Failure and then calling the GetMessageString() method.

When using -fwasm-exceptions e is of type WebAssembly.Exception and not a number any more, so that test fails. How can I extract any meaningful information from that exception, now? The wasm-internal representation of the Standard_Failure type seems to be opaque for me, which is why I cannot create a WebAssembly.Tag as suggested in the MDN docs (I think).

[donalffons]

...forgive me for not researching enough before asking. It seems like this issue is already being adressed in #16380 (and #16033).