Today users weren't able to sign up on our website in production.

The guilty code :

int ttl = 5256005760;

The first who find why will have a candy.

Integer overflow

When 01111111111111 go to 10000000000000

Funny fact : we were using this int to determine the expiration date to the activation link sended to the users.

expiration.setTime(currentTime + ttl);

- Why the fuck the expiration date is in the past....

*** Few minutes debugging later ***

- Oh shit the ttl is negative

#noluck

Where is my candy?

@stop I promise you, when sending candy will be a DevRant feature you'll have one!

@dfox Get on it! @stop needs his candy!

Can someone help me understand it?

In Binary you havent negative numbers. They use the first bit to indicate negative numbers
Example(binary is with b prefixed and decimal with d):
b0111 = d7
b0111 + b1 = b1000
b1000 = d-0

@stop Ah...no.
Actually, negative representation in binary it's managed by two complement of a number.

The 0 value is absolute, because it's two complement is still 0.

0 = 0000
TC of 0 = 1111 + 0001 = 0000 (carry one).

Thus, for example:

6 = 1010
-6 = 0101 + 0001 = 0110

@VacGamer actually, a gifting feature would be kind of cool. Even if it was just gifting rep. #scopecreep