rlmesh_last_error_code_str
The last error's code: writes the wire number of an RLMeshErrorCode (an environment class) or an RLMeshModelErrorCode (the model class) to *out and returns true; returns false with *out untouched for any other class. rlmesh_last_error_code_str() is the code's text ("BUSY"), or NULL with no code; valid until the next RLMesh call on this thread.
const char* rlmesh_last_error_code_str(void)