Date: Thu, 17 Mar 2016 08:21:12 +0100 From: Hans Petter Selasky <hps@selasky.org> To: Gleb Smirnoff <glebius@FreeBSD.org> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r296933 - in head: share/man/man9 sys/sys Message-ID: <56EA5AE8.4050700@selasky.org> In-Reply-To: <20160316203241.GM1328@FreeBSD.org> References: <201603160837.u2G8bqgr087126@repo.freebsd.org> <20160316203241.GM1328@FreeBSD.org>
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On 03/16/16 21:32, Gleb Smirnoff wrote: > On Wed, Mar 16, 2016 at 08:37:52AM +0000, Hans Petter Selasky wrote: > H> Author: hselasky > H> Date: Wed Mar 16 08:37:52 2016 > H> New Revision: 296933 > H> URL: https://svnweb.freebsd.org/changeset/base/296933 > H> > H> Log: > H> Improve the implementation and documentation of the > H> SYSCTL_COUNTER_U64_ARRAY() macro. > H> > H> - Add proper asserts to the SYSCTL_COUNTER_U64_ARRAY() macro that checks > H> the size of the first element of the array. > H> - Add an example to the counter(9) manual page how to use the > H> SYSCTL_COUNTER_U64_ARRAY() macro. > H> - Add some missing symbolic links for counter(9) while at it. > > ... > > H> +.Sh EXAMPLES > H> +The following example creates a static counter array exported to > H> +userspace through a sysctl: > H> +.Bd -literal -offset indent > H> +#define MY_SIZE 8 > H> +static counter_u64_t array[MY_SIZE]; > H> +SYSCTL_COUNTER_U64_ARRAY(_debug, OID_AUTO, counter_array, CTLFLAG_RW, > H> + &array[0], MY_SIZE, "Test counter array"); > > I always wondered what is stylistically better: array or &array[0]? I > usually prefer the former. > A question: If you pass "array" why do you need a length argument in the SYSCTL macro. Can't you get the length of the array like sizeof(array)/sizeof((array)[0]) inside the macro? --HPS
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