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: > > >> Il giorno 18/mag/2015, alle ore 23:34, Bruce Evans <brde@optusnet.com.au> ha scritto: >> >> On Mon, 18 May 2015, Pedro Giffuni wrote: >> >>>> Il giorno 18/mag/2015, alle ore 20:48, Bruce Evans <brde@optusnet.com.au> ha scritto: >>>> >>>>> On Mon, 18 May 2015, Pedro F. Giffuni wrote: >>>>> >>>>> Log: >>>>> ddb: stop boolean screaming. >>>>> >>>>> TRUE --> true >>>>> FALSE--> false >>>>> >>>>> Hinted by: NetBSD >>>> >>>> This is not just churn to a style regression, but a type mismatch. >>> >>> It is an attempt to reduce differences with NetBSD. >> >> For that, apply the reverse change to NetBSD. > > Actually, the NetBSD code uses bool. (I hate CVS, commits are not atomic.) > >>> 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. >> >> It is fairly well maintained (not churned to unimprove its portability). >> Why would newcomers want too look at it? > > Unrelated fun: last year a student started adding support for CTF and pretty printing of the kernel structures. I think the NetBSD guys have been having fun with Lua. > > >>>>> Modified: head/sys/ddb/db_break.c >>>>> ============================================================================== >>>>> --- head/sys/ddb/db_break.c Mon May 18 22:14:06 2015 (r283087) >>>>> +++ head/sys/ddb/db_break.c Mon May 18 22:27:46 2015 (r283088) >>>>> @@ -155,12 +155,12 @@ db_find_breakpoint_here(db_addr_t addr) >>>>> return db_find_breakpoint(db_map_addr(addr), addr); >>>>> } >>>>> >>>>> -static boolean_t db_breakpoints_inserted = TRUE; >>>>> +static boolean_t db_breakpoints_inserted = true; >>>> >>>> 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. >>> >>> Yes, I noticed the return types are still ints. It doesnft look difficult >>> to convert it to use a real boolean type. In any case, I would prefer to go >>> forward (using bool) instead of reverting this change. >> >> That wuld be sideways. >> >> I forgot to mention (again) in my previous reply that boolean_t is a mistake >> 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. >> >> 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. > > OK, I do understand the kernel wants to keep the C dialect somewhat limited, > and adding stdbool.h doesnft buy us any type safety here. > > Ifll revert the change (prob. tomorrow though). Too bad. You could just convert bool to an enum, add a compile-time assert, and chase down all of the -Werrors with clang... ... Nevermind. Not fun :(..
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