Date: Wed, 3 Sep 2014 22:17:37 -0600 From: Warner Losh <imp@bsdimp.com> To: Garrett Cooper <yaneurabeya@gmail.com> Cc: Julio Merino <jmmv@freebsd.org>, "rpaulo@freebsd.org" <rpaulo@freebsd.org>, freebsd-arch@freebsd.org Subject: Re: [RFC] Add __arraycount from NetBSD to sys/cdefs.h Message-ID: <8D279BDC-7D40-4750-8DA7-A4535DD2E458@bsdimp.com> In-Reply-To: <CAGHfRMBMPra5YXDn0e83dpVxwnarg3DL8o31xr7DhWv%2BVXskTg@mail.gmail.com> References: <CAGHfRMBMPra5YXDn0e83dpVxwnarg3DL8o31xr7DhWv%2BVXskTg@mail.gmail.com>
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[-- Attachment #1 --] On Sep 3, 2014, at 9:45 PM, Garrett Cooper <yaneurabeya@gmail.com> wrote: > Hi all, > In order to ease porting code and reduce divergence with NetBSD > when importing code (a large chunk of which for me are tests), I would > like to move nitems to sys/cdefs.h and alias __arraycount to nitems. > Here's the __arraycount #define in lib/libnetbsd/sys/cdefs.h: > > 44 /* > 45 * Return the number of elements in a statically-allocated array, > 46 * __x. > 47 */ > 48 #define __arraycount(__x) (sizeof(__x) / sizeof(__x[0])) > > Here's the nitems #define in sys/sys/param.h: > > 277 #define nitems(x) (sizeof((x)) / sizeof((x)[0])) > > sys/cdefs.h gets pulled in automatically with sys/param.h, so > anything using nitems will continue to function like before (see below > for more details). I've attached a patch which addresses all hardcoded > definitions in the tree added by FreeBSD developers. > If there aren't any major concerns with my proposed change, I'll > put it up for review on Phabricator. > Thank you! > -Garrett > > $ cat cdefs_pound_define.c > #include <sys/param.h> > > #ifdef _SYS_CDEFS_H_ > #warning "sys/cdefs.h has been included" > #endif > $ cc -c cdefs_pound_define.c > cdefs_pound_define.c:4:2: warning: "sys/cdefs.h has been included" [-W#warnings] > #warning "sys/cdefs.h has been included" > ^ > 1 warning generated. > $ cc -D_KERNEL -c cdefs_pound_define.c > cdefs_pound_define.c:4:2: warning: "sys/cdefs.h has been included" [-W#warnings] > #warning "sys/cdefs.h has been included" > ^ > 1 warning generated. > $ gcc -c cdefs_pound_define.c > cdefs_pound_define.c:4:2: warning: #warning "sys/cdefs.h has been included" > $ gcc -D_KERNEL -c cdefs_pound_define.c > cdefs_pound_define.c:4:2: warning: #warning "sys/cdefs.h has been included” I wouldn’t bother changing the nitems #define. There’s no need, really, to do that. I’d also be more inclined to believe the test if you tested what the thing does rather than test for an artificial, implementation defined side effect. But honestly the amount of duplication saved here is rather tiny… Warner [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Comment: GPGTools - https://gpgtools.org iQIcBAEBCgAGBQJUB+fhAAoJEGwc0Sh9sBEAjp4QAI7/yB+LvUkAmVM/O1DoX4wp /vbOT1awGQCWCsQGpT8r7PMIskfzwHve+JQxEfPoa8ddHVeaDuDTBw0P4YjLTDqW 828TdMCcQQ6/QpFxZooOxhAsnAwJErko+HmPy0q+JMUPlqresg8m5kADA0X9wU+4 NT1TxFjE5wdET7NyWqic0A2nP6Z7WewSbTfZmXqkz9N0abGl4Lu4uGB8lrfJwR/m NMco9Q5odpNXXjdi+RiGmM+I4HSQUkEu1s9mG0KSNIPdH+fdPlLDdSIkH+0RALB+ wi3s/xvyMZXYISXsH1IT+4qe+BtPX2PZI+HrsQIJOXlAhWj+yDbzko0Xl84yS7A/ pnx6uD46aK8w1JsjjCPNpj0cQ9e1K4bBaj7dHbkuInMszseAeKEnJcjMNLlZ6Flu 0DjNvLEDg0CRX56Bxm5vYuACdf7m8ly6zwOdEY1bHr2NQmFEEC5432BfX0z2dwNk 2rkA0Bjfq7y+dK3DUqVn/8qeZS03Pf57V30tWxNc5Prm/9FHme7LqHH7K68ROm3u LVqGMUR69iLTL6UB2+9MGdSmAcVijdsgL2UjB6LUtRffRlbsCrs5vx9sijCQkqEx 4O5tmBYI5gXlPD0809COnM1RpIODJersiLsGZtrNT91RhxFsSafJPviMsrbkWMe8 T8LtfmW+iq3rPeXwDkNr =wgEK -----END PGP SIGNATURE-----
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