 In general, then, a later test for a set "invalid" flag is needed to detect all cases where NaNs are introduced (see Function definition below for further details).In section 6.2 of the old IEEE 754-2008 standard, there are two anomalous functions (the codice_2 and codice_3 functions, which return the maximum of two operands that are expected to be numbers) that favor numbers — if just one of the operands is a NaN then the value of the other operand is returned.The IEEE 754-2019 revision has replaced these functions as they are not associative (when a signaling NaN appears in an operand).