Hacker News Reader

Comment by formerly_proven | Hacker News Reader

Specifically https://gist.github.com/FiloSottile/611fc3fa95c3aceebf258098...

    -    if (written_out > max_out)
    +    if (written_out >= max_out)
             return 0;

Plus a second, less memeable fix.

View on HN

I don't understand this one:

     -                (written_out - i) * sizeof *pDecoded);
     +                (written_out - i) * sizeof(*pDecoded));

Edit: just to be clear-- I'm claiming there's no way the addition of parentheses could change the behavior of the program.

I guess I can understand resolving an ambiguity so that the reader doesn't have to look up precedence rules. But when combined with a high-profile bug in a critical piece of infrastructure it looks a bit like the software equivalent of not shaving one's beard in the hopes of winning a sports tournament.

Looks to me like a coding style fix along for the ride with the correctness fix.

I don't think that's security-relevant, likely just keeping a linter happy.

Ah, I didn't think about a linter. I'll take a look at the code later to see if that's the case.

sizeof is a keyword because of some terrible reason, but I'd parenthesize it just to make the intention clear.

Why is sizeof a terrible keyword? Just think of it as an operator rather than a function.

Should have been a callable, or should have had consistent syntax to prevent people from being clever.

Agreed. sizeof FEELS like a function, and so I use parentheses with it, even though I know it's not actually a function.

Wasn't there some subtle difference between using sizeof with vs without parens? Something like if you pass a type to sizeof -- e.g. sizeof(*int) -- you must use parents anyway? It's been years since I've used C, I'm probably not remembering it correctly.

Yes, exactly that. `sizeof(int)` OK, `sizeof(i)` OK, `sizeof i` OK, `sizeof int` not OK. One of those weird rules.

From the variable names, it is clear that the old version was correct. Someone should revert this. :-)

Reply on news.ycombinator.com