On Fri 09-03-18 12:05:35, Thomas Gleixner wrote: > On Fri, 9 Mar 2018, Jan Kara wrote: > > > Hum, what is 'VLA'? > > Variable Length Array. They are allocated on stack and sized at runtime. > Those are bad for obvious reasons and should have never been allowed in C > in the first place. clang does not support them for really good reasons. > > > And why do we want to replace easy to understand strlen() with sizeof() > > where I had to think and actually look up what the C standard says about > > a sizeof(string literal). > > The issue is, that strlen() results in actual runtime evaluation instead of > the compiler being clever and figuring out that it is a compile time > constant. And runtime evaluation creates a VLA. > > Using sizeof() forces the compiler to evaluate it at compile time, so it's > just a compile time sized array on stack. Ah, thanks for explanation! Now the patch makes much more sense :). I'll cut-n-paste your explanation to the patch changelog and take it to my tree. Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR -- To unsubscribe from this list: send the line "unsubscribe reiserfs-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
