(Linus and Andrew Cc:-ed) * Thomas Gleixner <[email protected]> wrote:
> On Tue, 7 Mar 2017, Ingo Molnar wrote: > > > > * kbuild test robot <[email protected]> wrote: > > > > > arch/x86/kernel/fpu/xstate.c:931:9-10: WARNING: return of 0/1 in function > > > 'xfeatures_mxcsr_quirk' with return type bool > > > > > > Return statements in functions returning bool should use > > > true/false instead of 1/0. > > > > Note that this is a totally bogus warning. I personally find a 0/1 return > > more > > readable than a textual 'true/false', even if bools are used, and nowhere > > does the > > kernel mandate the use of 0/1. > > I disagree. > > The fact that booleans have been brought retroactively into the C-Standard > does and for compability reasons C still follows the approach "Boolean > values are just integers" does not make it any better. > > We had stupid bugs, where people returned -EINVAL from a boolean function > and introduced silly and hard to understand bugs. But this function is not using -EINVAL, it's using 0 and 1 which is both correct and unambiguous! I mean, if the Cocci script warned about -EINVAL then it would have found a clear bug. Now it's warning about the use of 0/1 literals with bool types which is perfectly legal, readable, clear C code! > The canonical values assigned to booleans are 'true' and 'false' and not > whatever people prefer. Can we please be consistent on that? I think that's backwards, because 1/0 is just as canonical for true/false, and to me personally it's in fact easier to read as well. I would really like higher level buy-in for that principle (I've Cc:-ed Linus and Andrew), and if indeed the consensus is that '0/1' cannot be used with 'bool' then I'll remove all uses of 'bool' from my patches and from code I care about and use 'int' instead. Please update Documentation/CodingStyle accordingly as well. To me a lexical 'true/false' instead of '1/0' is a step backwards in readability in many cases - using the slightly wider 'int' type is the lesser evil. Thanks, Ingo
