Retrieving error message after mj_compile fails (C API)

[Pierre-Terdiman]

Intro

Hello, I am interested in physics engines and starting to learn MuJoCo.

My setup

MuJoCo 3.2.2, C API, Windows

My question

Sometimes the model compilation fails and all I have is a null pointer, and no information about what went wrong.

I did setup mju_user_error and mju_user_warning but they are not called in this case.

Tracing the code, I see that the error message that would be useful for diagnostics is available in "modelC->errInfo" right before mj_compile returns:

mjModel* mj_compile(mjSpec* s, const mjVFS* vfs) {
  mjCModel* modelC = static_cast<mjCModel*>(s->element);
  return modelC->Compile(vfs);
}

But as far as I can tell that class is not visible from the user's side of the API, so that error cannot be accessed there. Is there a way to retrieve that error message? Or is there an error callback I missed, that would let me catch that error?

Thank you.

Minimal model and/or code that explain my question

No response

Confirmations

• I searched the latest documentation thoroughly before posting.
• I searched previous Issues and Discussions, I am certain this has not been raised before.

[Pierre-Terdiman]

nvm, found "mjs_getError" just after posting (of course)

[oursland]

Also note mjs_isWarning(), which will inform you if there's a warning which you may also retrieve with mjs_getError(). Example in src/xml/xml_api.cc::mj_loadXML()

[Pierre-Terdiman]

Thank you, I added that as well.