rlmesh_error_class_name
The name of a class ("ConnectionError"), static; NULL for INVALID or an unknown value. rlmesh_error_class_is_subclass tests class inheritance: it is reflexive and transitive over the class hierarchy. CONNECTION_ERROR is a subclass of OS_ERROR; the general error classes are not subclasses of RLMESH_EXCEPTION.
const char* rlmesh_error_class_name(RLMeshErrorClass cls)