IN: The length of the class name to be returned by this function
H5E_GET_CLASS_NAME retrieves the name of the error class specified by the class identifier. If non-NULL pointer is passed in for name and size is greater than zero, the class name of size long is returned. The length of the error class name is also returned. If NULL is passed in as name, only the length of class name is returned. If zero is returned, it means no name. User is responsible for allocated enough buffer for the name.
Returns non-negative value as on success; otherwise returns negative value.