On Tue, 23 Jun 2015, Dan Carpenter wrote: > On Tue, Jun 23, 2015 at 08:25:05AM +0000, Dilger, Andreas wrote: > > I've found in the past that developers can introduce bugs when they treat > > return values as boolean when they really aren't. > > I can imagine a bug like that where a function can return 0-2 and people > do: > > if (ret) > > instead of: > > if (ret == 1) > > but that bug is something else besides pointers so it doesn't apply > here. > > What someone should do is try to measure it scientifically where we > flash some code on the screen and you have to press J for NULL and K for > non-NULL and we time it to the hundredth of a second. I have a feeling > that (NULL != foo) is the worst way to write it because of the double > negative Yoda code. > > Yoda code is the most useless thing ever. I have actually measured this > and we introduce about 2 = vs == bugs per year. It's probably less now > that we have so many static checks against it. But people decided that > Yoda code was a good idea based on their gut instead of using statistics > and measurements and science. In 2007, Al Viro said (https://lkml.org/lkml/2007/7/27/103): Idiomatic form for "has allocation succeeded?" is neither "if (p != 0)" nor "if (p != NULL)". It's simply "if (p)". >From the point of view of looking at kernel code, x == NULL for the result of kmalloc etc looks verbose and distracting. julia -- To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
