[int_19h]

> The main difference I know of is that file descriptors are sequential, while handles are random.

Is it an API guarantee, or just an irrelevant implementation detail?

[cesarb]

For file descriptors, API guarantee, specified by POSIX: http://pubs.opengroup.org/onlinepubs/9699919799/functions/V2...

"[...] atomically allocate the lowest numbered available (that is, not already open in the calling process) file descriptor [...]"