Internal method to be used by widgets including this mixin. It can only be used when a Efl.Ui.Format.format_string has been supplied, and it returns the number of decimal places that the format string will produce for floating point values.
For example, "%.2f" returns 2, and "%d" returns 0;
Since 1.23
decimal_places_get @protected { return: int; }
int efl_ui_format_decimal_places_get(Eo *obj);