serial data type limit

Hi!

I'm new to Pg and I understand that serial data type is an int4 numeric
type.
What will happen to the serial data type if it has reach the limit of int4
(+2147483647)? Will it return zero?

Thanks in advance.

Numeric type | Storage  | Range
int4         | 4 bytes  | -2147483648 to +2147483647