Date: Mon, 18 May 2015 22:56:31 -0700 From: Garrett Cooper <yaneurabeya@gmail.com> To: Pedro Giffuni <pfg@FreeBSD.org> Cc: Bruce Evans <brde@optusnet.com.au>, "src-committers@freebsd.org" <src-committers@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "svn-src-head@freebsd.org" <svn-src-head@freebsd.org> Subject: Re: svn commit: r283088 - head/sys/ddb Message-ID: <161C0DB1-E570-4A92-A98B-4098C510E96B@gmail.com> In-Reply-To: <BA474AEC-A0A8-4FF8-8881-397E8280C72F@FreeBSD.org> References: <201505182227.t4IMRljx078812@svn.freebsd.org> <20150519113755.U1840@besplex.bde.org> <406A7AE3-1891-4B2C-B917-14C150EBBAB5@FreeBSD.org> <20150519135341.R2157@besplex.bde.org> <BA474AEC-A0A8-4FF8-8881-397E8280C72F@FreeBSD.org>
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> On May 18, 2015, at 22:28, Pedro Giffuni <pfg@FreeBSD.org> wrote: >=20 >=20 >> Il giorno 18/mag/2015, alle ore 23:34, Bruce Evans <brde@optusnet.com.au>= ha scritto: >>=20 >> On Mon, 18 May 2015, Pedro Giffuni wrote: >>=20 >>>> Il giorno 18/mag/2015, alle ore 20:48, Bruce Evans <brde@optusnet.com.a= u> ha scritto: >>>>=20 >>>>> On Mon, 18 May 2015, Pedro F. Giffuni wrote: >>>>>=20 >>>>> Log: >>>>> ddb: stop boolean screaming. >>>>>=20 >>>>> TRUE --> true >>>>> FALSE--> false >>>>>=20 >>>>> Hinted by: NetBSD >>>>=20 >>>> This is not just churn to a style regression, but a type mismatch. >>>=20 >>> It is an attempt to reduce differences with NetBSD. >>=20 >> For that, apply the reverse change to NetBSD. >=20 > Actually, the NetBSD code uses bool. (I hate CVS, commits are not atomic.)= >=20 >>> One of the complaints of hear from newcomers to the ddb code is that >>> the format is old-fashioned (it still had pre-ANSI headers not long ago)= >>> and unmaintained. >>=20 >> It is fairly well maintained (not churned to unimprove its portability). >> Why would newcomers want too look at it? >=20 > Unrelated fun: last year a student started adding support for CTF and pret= ty printing of the kernel structures. I think the NetBSD guys have been havi= ng fun with Lua. >=20 >=20 >>>>> Modified: head/sys/ddb/db_break.c >>>>> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D >>>>> --- head/sys/ddb/db_break.c Mon May 18 22:14:06 2015 (r2= 83087) >>>>> +++ head/sys/ddb/db_break.c Mon May 18 22:27:46 2015 (r2= 83088) >>>>> @@ -155,12 +155,12 @@ db_find_breakpoint_here(db_addr_t addr) >>>>> return db_find_breakpoint(db_map_addr(addr), addr); >>>>> } >>>>>=20 >>>>> -static boolean_t db_breakpoints_inserted =3D TRUE; >>>>> +static boolean_t db_breakpoints_inserted =3D true; >>>>=20 >>>> This code hasn't been churned to use the boolean type. It still uses >>>> boolean_t, which is plain int. TRUE and FALSE go with this type. true= >>>> and false go with the boolean type. This probably makes no difference,= >>>> because TRUE happens to be implemented with the same value as true and >>>> there are lots of implicit versions between the types. >>>=20 >>> Yes, I noticed the return types are still ints. It doesn=81ft look diffi= cult >>> to convert it to use a real boolean type. In any case, I would prefer t= o go >>> forward (using bool) instead of reverting this change. >>=20 >> That wuld be sideways. >>=20 >> I forgot to mention (again) in my previous reply that boolean_t is a mist= ake >> by me. KNF code doesn't even use the ! operator, but uses explicit >> comparison with 0. The boolean_t type and TRUE and FALSE are from Mach. >> They were used mainly in ddb and vm, and are still almost never used in >> kern. I used to like typedefs and a typedef for boolean types, and didn'= t >> know KNF very well, so in 1995 I moved the declaration of boolean_t from >> Mach vm code to sys/types.h to try to popularize it. This was a mistake.= >> Fortunately, it is still rarely used in core kernel code. >>=20 >> The boolean type is also almost never used for syscalls. In POSIX.1-2001= , >> <stdbool.h> is inherited from C99, but is never used for any other POSIX >> API. Using it for syscalls would mainly cause portability problems. >=20 > OK, I do understand the kernel wants to keep the C dialect somewhat limite= d, > and adding stdbool.h doesn=81ft buy us any type safety here. >=20 > I=81fll revert the change (prob. tomorrow though). Too bad. You could just convert bool to an enum, add a compile-time assert, a= nd chase down all of the -Werrors with clang... ... Nevermind. Not fun :(..=
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