@param s Pointer to the tag data, as returned by bam_aux_get().
@param idx 0-based Index into the array
@return The idx'th value, or 0.0 on error.
If the array is not a numeric type, errno is set to EINVAL. This can
only actually happen if the input record has an invalid type field. If
idx is greater than or equal to the value returned by bam_auxB_len(s),
errno is set to ERANGE. In both cases, 0.0 will be returned.
@param s Pointer to the tag data, as returned by bam_aux_get(). @param idx 0-based Index into the array @return The idx'th value, or 0.0 on error. If the array is not a numeric type, errno is set to EINVAL. This can only actually happen if the input record has an invalid type field. If idx is greater than or equal to the value returned by bam_auxB_len(s), errno is set to ERANGE. In both cases, 0.0 will be returned.