Date: Fri, 1 Jan 2010 11:51:41 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-7@freebsd.org Subject: svn commit: r201363 - in stable/7/lib/libc: gen sys Message-ID: <201001011151.o01Bpfbc004905@svn.freebsd.org>
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Author: kib Date: Fri Jan 1 11:51:40 2010 New Revision: 201363 URL: http://svn.freebsd.org/changeset/base/201363 Log: MFC r201201: Document CLOCK_SECOND, add cross-reference from time(3) to clock_gettime(2). MFC r201204: Document _FAST and _PRECISE clocks. Modified: stable/7/lib/libc/gen/time.3 stable/7/lib/libc/sys/clock_gettime.2 Directory Properties: stable/7/lib/libc/ (props changed) stable/7/lib/libc/stdtime/ (props changed) Modified: stable/7/lib/libc/gen/time.3 ============================================================================== --- stable/7/lib/libc/gen/time.3 Fri Jan 1 11:43:09 2010 (r201362) +++ stable/7/lib/libc/gen/time.3 Fri Jan 1 11:51:40 2010 (r201363) @@ -66,6 +66,7 @@ The function may fail for any of the reasons described in .Xr gettimeofday 2 . .Sh SEE ALSO +.Xr clock_gettime 2 , .Xr gettimeofday 2 , .Xr ctime 3 .Sh STANDARDS Modified: stable/7/lib/libc/sys/clock_gettime.2 ============================================================================== --- stable/7/lib/libc/sys/clock_gettime.2 Fri Jan 1 11:43:09 2010 (r201362) +++ stable/7/lib/libc/sys/clock_gettime.2 Fri Jan 1 11:51:40 2010 (r201363) @@ -29,7 +29,7 @@ .\" .\" $FreeBSD$ .\" -.Dd November 4, 2006 +.Dd December 29, 2009 .Dt CLOCK_GETTIME 2 .Os .Sh NAME @@ -59,21 +59,43 @@ used by a clock which is specified by The .Fa clock_id argument -can be one of five values: -.Dv CLOCK_REALTIME +can be one of the following values: +.Dv CLOCK_REALTIME , +.Dv CLOCK_REALTIME_PRECISE , +.Dv CLOCK_REALTIME_FAST for time that increments as -a wall clock should, -.Dv CLOCK_MONOTONIC -which increments in SI seconds, -.Dv CLOCK_UPTIME +a wall clock should; +.Dv CLOCK_MONOTONIC , +.Dv CLOCK_MONOTONIC_PRECISE , +.Dv CLOCK_MONOTONIC_FAST +which increments in SI seconds; +.Dv CLOCK_UPTIME , +.Dv CLOCK_UPTIME_PRECISE , +.Dv CLOCK_UPTIME_FAST which starts at zero when the kernel boots and increments -monotonically in SI seconds while the machine is running, +monotonically in SI seconds while the machine is running; .Dv CLOCK_VIRTUAL for time that increments only when -the CPU is running in user mode on behalf of the calling process, or +the CPU is running in user mode on behalf of the calling process; .Dv CLOCK_PROF for time that increments when the CPU is running in user or -kernel mode. +kernel mode; or +.Dv CLOCK_SECOND +which returns the current second without performing a full time counter +query, using in-kernel cached value of current second. +.Pp +The clock IDs +.Fa CLOCK_REALTIME_FAST , +.Fa CLOCK_MONOTONIC_FAST , +.Fa CLOCK_UPTIME_FAST +are analogs of corresponding IDs without _FAST suffix but do not perform +a full time counter query, so their accuracy is one timer tick. +Similarly, +.Fa CLOCK_REALTIME_PRECISE , +.Fa CLOCK_MONOTONIC_PRECISE , +.Fa CLOCK_UPTIME_PRECISE +are used to get the most exact value as possible, at the expense of +execution time. .Pp The structure pointed to by .Fa tp @@ -88,7 +110,8 @@ struct timespec { }; .Ed .Pp -Only the super-user may set the time of day. +Only the super-user may set the time of day, using only +.Fa CLOCK_REALTIME . If the system securelevel is greater than 1 (see .Xr init 8 ) , the time may only be advanced. @@ -134,3 +157,13 @@ and .Fn clock_getres system calls conform to .St -p1003.1b-93 . +The clock IDs +.Fa CLOCK_REALTIME_FAST , +.Fa CLOCK_REALTIME_PRECISE , +.Fa CLOCK_MONOTONIC_FAST , +.Fa CLOCK_MONOTONIC_PRECISE , +.Fa CLOCK_UPTIME , +.Fa CLOCK_UPTIME_FAST , +.Fa CLOCK_UPTIME_PRECISE , +.Fa CLOCK_SECOND +are FreeBSD extensions to the POSIX interface.
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