[L3viathan]

Nitpick, but:

> At its core, a file descriptor (often abbreviated as fd) is simply a positive integer

A _non-negative_ integer.

[DougN7]

Ok, I have to ask: the difference between “positive” and “non-negative” is …?

[cesarb]

The integer numbers can be divided into "negative" (less than zero), zero, and "positive" (greater than zero). When one says "non-negative", they are excluding only the negative numbers, so zero is included; when one says "positive", zero is not included.

[bregma]

The difference is a classic off-by-one error that can lead to a security exploit.

[magicalhippo]

Positive numbers are greater than zero[1], while non-negative numbers are greater or equal to zero.

[1]: https://en.wikipedia.org/wiki/List_of_types_of_numbers#Signe...

[rkomorn]

0 is non-negative but also... non-positive?