Error messages and function names/line numbers are traced via
__func__ or __FUNCTION__, __LINE__, etc (or just "unknown" if
not available). A manual stack is kept onto which these values
are pushed which can then be dumped to stderr/stdout.
stderr is used to report this information since no other
facility appears to be provided.
The get_frame code always assumed a dataset rank of three, so this
doesn't actually change much, but its one less dynamically allocated
buffer to keep track of.
Charles Mita