addu

fnuint addu()(uint x, uint y, ref bool overflow)

Add two unsigned integers, checking for overflow (aka carry).

The overflow is sticky, meaning a sequence of operations can be done and overflow need only be checked at the end.

`x`	left operand
`y`	right operand
`overflow`	set if an overflow occurs, is not affected otherwise

the sum

fnulong addu()(ulong x, ulong y, ref bool overflow)

ditto