[nkurz]

That's fair, although it seems like in that case TARSNAP_FAILURE and TARSNAP_SUCCESS would then be a fine alternative.

I think the whole question is how much it's OK to have an house style that isn't immediately accessible, and how much that benefits the project. Is it really a benefit if outsiders can grasp the code immediately, or is it actually good to have a hurdle?

Do you have an argument against "rehash(H) < 0" other than the visual distraction? It seems like it would parallel better with a literal comparison to NULL.

[cperciva]

TARSNAP_FAILURE and TARSNAP_SUCCESS would then be a fine alternative

Sure, until someone looking at kivaloo or spiped or scrypt asks "what the heck is tarsnap?" ;-)

house style that isn't immediately accessible

I think it's very likely that people working on the kivaloo code will have at least a passing familiarity with UNIX system call conventions, and would find my house style entirely accessible.

Do you have an argument against "rehash(H) < 0" other than the visual distraction?

I would interpret that to indicate that the function has several potential return codes, not just 0 or -1.