Date: Thu, 5 May 2016 21:14:49 +1000 (EST) From: Bruce Evans <brde@optusnet.com.au> To: Konstantin Belousov <kostikbel@gmail.com> Cc: John Baldwin <jhb@freebsd.org>, Bruce Evans <brde@optusnet.com.au>, Pedro Giffuni <pfg@freebsd.org>, "Ngie Cooper (yaneurabeya)" <yaneurabeya@gmail.com>, src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r298933 - in head: share/man/man9 sys/amd64/include sys/dev/acpica sys/dev/drm2 sys/dev/drm2/i915 sys/kern sys/sys sys/x86/acpica sys/x86/x86 Message-ID: <20160505203633.Y2142@besplex.bde.org> In-Reply-To: <20160505084222.GD2422@kib.kiev.ua> References: <201605021800.u42I0cjK084243@repo.freebsd.org> <20160504031930.A3395@besplex.bde.org> <1928389.rOu33C1eaq@ralph.baldwin.cx> <2067797.hs1zGgLCXN@ralph.baldwin.cx> <20160505084222.GD2422@kib.kiev.ua>
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On Thu, 5 May 2016, Konstantin Belousov wrote: > On Wed, May 04, 2016 at 09:17:50PM -0700, John Baldwin wrote: >> ... >> How about this: >> ... >> diff --git a/sys/sys/_bitset.h b/sys/sys/_bitset.h >> index 26a8848..89dd7b6 100644 >> --- a/sys/sys/_bitset.h >> +++ b/sys/sys/_bitset.h >> @@ -36,26 +36,15 @@ >> * Macros addressing word and bit within it, tuned to make compiler >> * optimize cases when SETSIZE fits into single machine word. >> */ >> -#define _BITSET_BITS (sizeof(long) * NBBY) >> +#define _BITSET_BITS (sizeof(long) * 8) >> >> -#define __bitset_words(_s) (howmany(_s, _BITSET_BITS)) >> +#define _howmany(x, y) (((x) + ((y) - 1)) / (y)) > The _howmany symbol is still in the user namespace. Implementation-reserved > names are __.* and _[A-Z].* . The names _.* also are reserved at file scope. sys/select.h also uses _howmany(), and that is correct there since it is only used in inner scopes that the application cannot conflict with (except possibly via -Wshadow warnings). I haven't checked this in the patch yet, but it is probably the same. In select.h, the inner scopes are one inside a struct declaration and one inside a compound statement in a statement-like macro. I like to use minimal underscores since 2 underscores are uglier. select.h does this perfectly or almost perfectly. An example of this is the __fd_mask typedef. This is used in non-inner scopes so it needs 2 underscores. The above fixes the bogus underscore on _s. 1 underscore is also ugly, and this one shows lack of understanding of namespaces. Underscores are never needed for macro parameters since they create their their own namespace. Brucehome | help
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