This function returns 0 for success, in which case:
results contains the current values for type all of the subtypes in e.
type_name_disposition contains information on how each type was matched. Valid values are
actual_type_name contains the type name as found.
buffer_flags contains the bit mask to be used as input flags for slapi_vattr_values_free().
subtype_count contains the number of subtypes matched.
Otherwise, this function returns the following
SLAPI_VIRTUALATTRS_LOOP_DETECTED (failed to evaluate a virtual attribute).
SLAPI_VIRTUAL_NOT_FOUND (type not recognized by any virtual attribute and not a real attr in entry).
ENOMEM (memory error).