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[linuxjm/jm.git] / manual / LDP_man-pages / draft / man2 / clock_getres.2

.\" Hey Emacs! This file is -*- nroff -*- source.
.\"
.\" Copyright (c) 2003 Nick Clifford (zaf@nrc.co.nz), Jan 25, 2003
.\" Copyright (c) 2003 Andries Brouwer (aeb@cwi.nl), Aug 24, 2003
.\"
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
.\" Permission is granted to copy and distribute modified versions of this
.\" manual under the conditions for verbatim copying, provided that the
.\" entire resulting derived work is distributed under the terms of a
.\" permission notice identical to this one.
.\"
.\" Since the Linux kernel and libraries are constantly changing, this
.\" manual page may be incorrect or out-of-date.  The author(s) assume no
.\" responsibility for errors or omissions, or for damages resulting from
.\" the use of the information contained herein.  The author(s) may not
.\" have taken the same level of care in the production of this manual,
.\" which is licensed free of charge, as they might when working
.\" professionally.
.\"
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.\"
.\" 2003-08-23 Martin Schulze <joey@infodrom.org> improvements
.\" 2003-08-24 aeb, large parts rewritten
.\" 2004-08-06 Christoph Lameter <clameter@sgi.com>, SMP note
.\"
.\" Japanese Version Copyright (c) 2004-2005 Yuichi SATO
.\"         all rights reserved.
.\" Translated 2004-07-19, Yuichi SATO <ysato444@yahoo.co.jp>
.\" Updated & Modified 2005-01-10, Yuichi SATO
.\" Updated 2010-04-11, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>
.\"
.TH CLOCK_GETRES 2 2010-02-03 "" "Linux Programmer's Manual"
.\"O .SH NAME
.SH ̾Á°
.\"O clock_getres, clock_gettime, clock_settime \- clock and time functions
clock_getres, clock_gettime, clock_settime \- ¥¯¥í¥Ã¥¯¤È»þ´Ö¤Î´Ø¿ô
.\"O .SH SYNOPSIS
.SH ½ñ¼°
.B #include <time.h>
.sp
.BI "int clock_getres(clockid_t " clk_id ", struct timespec *" res );

.BI "int clock_gettime(clockid_t " clk_id ", struct timespec *" tp );

.BI "int clock_settime(clockid_t " clk_id ", const struct timespec *" tp );
.sp
.\"O Link with \fI\-lrt\fP.
\fI\-lrt\fP ¤È¥ê¥ó¥¯¤¹¤ë¡£
.sp
.in -4n
.\"O Feature Test Macro Requirements for glibc (see
.\"O .BR feature_test_macros (7)):
glibc ¸þ¤±¤Îµ¡Ç½¸¡ºº¥Þ¥¯¥í¤ÎÍ×·ï
.RB ( feature_test_macros (7)
»²¾È):
.in
.sp
.ad l
.BR clock_getres (),
.BR clock_gettime (),
.BR clock_settime ():
_POSIX_C_SOURCE\ >=\ 199309L
.ad b
.\"O .SH DESCRIPTION
.SH ÀâÌÀ
.\"O The function
.\"O .BR clock_getres ()
.\"O finds the resolution (precision) of the specified clock
.\"O .IR clk_id ,
.\"O and, if
.\"O .I res
.\"O is non-NULL, stores it in the \fIstruct timespec\fP pointed to by
.\"O .IR res .
´Ø¿ô
.BR clock_getres ()
¤Ï
»ØÄꤵ¤ì¤¿¥¯¥í¥Ã¥¯
.I clk_id
¤Îʬ²òǽ (ÀºÅÙ) ¤òõ¤·½Ð¤¹¡£
.I res
¤¬ NULL ¤Ç¤Ê¤¤¾ì¹ç¡¢¤½¤Îʬ²òǽ¤ò
.I res
¤Ç»Ø¤µ¤ì¤ë \fIstruct timespec\fP ¤Ë³ÊǼ¤¹¤ë¡£
.\"O The resolution of clocks depends on the implementation and cannot be
.\"O configured by a particular process.
¥¯¥í¥Ã¥¯¤Îʬ²òǽ¤Ï¼ÂÁõ¤Ë°Í¸¤·¡¢
ÆÃÄê¤Î¥×¥í¥»¥¹¤Ë¤è¤Ã¤ÆÀßÄꤹ¤ë¤³¤È¤Ï¤Ç¤­¤Ê¤¤¡£
.\"O If the time value pointed to by the argument
.\"O .I tp
.\"O of
.\"O .BR clock_settime ()
.\"O is not a multiple of
.\"O .IR res ,
.\"O then it is truncated to a multiple of
.\"O .IR res .
.BR clock_settime ()
¤Î°ú¤­¿ô
.I tp
¤Ç»Ø¤µ¤ì¤ë»þ´Ö¤ÎÃͤ¬
.I res
¤ÎÇÜ¿ô¤Ç¤Ê¤¤¾ì¹ç¡¢
.I res
¤ÎÇÜ¿ô¤ËÀÚ¤êµÍ¤á¤é¤ì¤ë¡£
.PP
.\"O The functions
.\"O .BR clock_gettime ()
.\"O and
.\"O .BR clock_settime ()
.\"O retrieve and set the time of the specified clock
.\"O .IR clk_id .
´Ø¿ô
.BR clock_gettime ()
¤È
.BR clock_settime ()
¤Ï¡¢»ØÄꤵ¤ì¤¿¥¯¥í¥Ã¥¯
.I clk_id
¤Î»þ´Ö¤ò¼èÆÀ¤Þ¤¿¤ÏÀßÄꤹ¤ë¡£
.PP
.\"O The
.\"O .I res
.\"O and
.\"O .I tp
.\"O arguments are
.\"O .I timespec
.\"O structures, as specified  in
.\"O .IR <time.h> :
.I res
¤È
.I tp
°ú¤­¿ô¤Ï
.I timespec
¹½Â¤ÂΤǤ¢¤ê¡¢
.I <time.h>
¤Ç°Ê²¼¤Î¤è¤¦¤Ëµ¬Äꤵ¤ì¤Æ¤¤¤ë:
.sp
.in +4n
.nf
struct timespec {
    time_t   tv_sec;        /* seconds */
    long     tv_nsec;       /* nanoseconds */
};
.fi
.in
.PP
.\"O The
.\"O .I clk_id
.\"O argument is the identifier of the particular clock on which to act.
.I clk_id
°ú¤­¿ô¤ÏÆÃÄê¤Î¥¯¥í¥Ã¥¯¤Î¼±Ê̻ҤǤ¢¤ê¡¢¤½¤Î¥¯¥í¥Ã¥¯¤ÇÆ°ºî¤¹¤ë¡£
.\"O A clock may be system-wide and hence visible for all processes, or
.\"O per-process if it measures time only within a single process.
¥¯¥í¥Ã¥¯¤Ï¥·¥¹¥Æ¥àÁ´ÂΤËŬÍѤ¹¤ë¤³¤È¤â¤Ç¤­¡¢
¤½¤Î¾ì¹ç¤ÏÁ´¤Æ¤Î¥×¥í¥»¥¹¤«¤é¸«¤ë¤³¤È¤¬¤Ç¤­¤ë¡£
¤Þ¤¿ 1 ¤Ä¤Î¥×¥í¥»¥¹Æâ¤Ç¤Î¤ß»þ´Ö¤ò·×¬¤¹¤ë¾ì¹ç¤Ï¡¢
¥×¥í¥»¥¹Ëè¤ËŬÍѤ¹¤ë¤³¤È¤â¤Ç¤­¤ë¡£
.LP
.\"O All implementations support the system-wide real-time clock,
.\"O which is identified by
.\"O .BR CLOCK_REALTIME .
Á´¤Æ¤Î¼ÂÁõ¤Ë¤ª¤¤¤Æ¥·¥¹¥Æ¥àÁ´ÂΤΥꥢ¥ë¥¿¥¤¥à¥¯¥í¥Ã¥¯¤¬¥µ¥Ý¡¼¥È¤µ¤ì¡¢
.B CLOCK_REALTIME
¤Ç¼±Ê̤µ¤ì¤ë¡£
.\"O Its time represents seconds and nanoseconds since the Epoch.
»þ´Ö¤Ïµª¸µ (the Epoch) ¤«¤é¤ÎÉäȥʥÎÉäÇɽ¤µ¤ì¤ë¡£
.\"O When its time is changed, timers for a relative interval are
.\"O unaffected, but timers for an absolute point in time are affected.
»þ´Ö¤¬Êѹ¹¤µ¤ì¤¿¾ì¹ç¡¢ÁêÂÐŪ¤Ê»þ´Ö´Ö³Ö¤Î¥¿¥¤¥Þ¤Ï±Æ¶Á¤ò¼õ¤±¤Ê¤¤¤¬¡¢
ÀäÂÐŪ¤Ê»þÅÀ¤Î¥¿¥¤¥Þ¤Ï±Æ¶Á¤ò¼õ¤±¤ë¡£
.LP
.\"O More clocks may be implemented.
.\"O The interpretation of the
.\"O corresponding time values and the effect on timers is unspecified.
¤µ¤é¤Ë¤¤¤¯¤Ä¤«¤Î¥¯¥í¥Ã¥¯¤¬¼ÂÁõ¤µ¤ì¤Æ¤¤¤ë¤«¤â¤·¤ì¤Ê¤¤¡£
Âбþ¤¹¤ë»þ´Ö¤ÎÃͤò²ò¼á¤¹¤ëÊýË¡¤È¥¿¥¤¥Þ¤Ø¤Î±Æ¶Á¤Ï¡¢Äê¤á¤é¤ì¤Æ¤¤¤Ê¤¤¡£
.LP
.\"O Sufficiently recent versions of glibc and the Linux kernel
.\"O support the following clocks:
glibc ¤È Linux ¥«¡¼¥Í¥ë¤ÎºÇ¿·¤Î¥Ð¡¼¥¸¥ç¥ó¤Ç¤Ï¡¢
°Ê²¼¤Î¤è¤¦¤Ê½½Ê¬¤Ê¥¯¥í¥Ã¥¯¤¬¥µ¥Ý¡¼¥È¤µ¤ì¤Æ¤¤¤ë¡£
.TP
.B CLOCK_REALTIME
.\"O System-wide real-time clock.
¥·¥¹¥Æ¥àÁ´ÂΤΥꥢ¥ë¥¿¥¤¥à¥¯¥í¥Ã¥¯¡£
.\"O Setting this clock requires appropriate privileges.
¤³¤Î¥¯¥í¥Ã¥¯¤òÀßÄꤹ¤ë¤Ë¤ÏŬÀÚ¤ÊÆø¢¤¬É¬ÍפǤ¢¤ë¡£
.TP
.B CLOCK_MONOTONIC
.\"O Clock that cannot be set and represents monotonic time since
.\"O some unspecified starting point.
¤¤¤¯¤Ä¤«¤Î³«»ÏÅÀ¤¬»ØÄꤵ¤ì¤Æ¤¤¤Ê¤¤¤¿¤á¡¢
¥¯¥í¥Ã¥¯¤¬¥â¥Î¥È¥Ë¥Ã¥¯¥¿¥¤¥à¤òÀßÄꤷ¤¿¤êɽ¸½¤·¤¿¤ê¤Ç¤­¤Ê¤¤¡£
.TP
.\"O .BR CLOCK_MONOTONIC_RAW " (since Linux 2.6.28; Linux-specific)"
.BR CLOCK_MONOTONIC_RAW " (Linux 2.6.28 °Ê¹ß; Linux ÆÃÍ­)"
.\" Added in commit 2d42244ae71d6c7b0884b5664cf2eda30fb2ae68, John Stultz
.\"O Similar to
.\"O .BR CLOCK_MONOTONIC ,
.\"O but provides access to a raw hardware-based time
.\"O that is not subject to NTP adjustments.
.B CLOCK_MONOTONIC
¤ÈƱÍͤÀ¤¬¡¢NTP ¤Ë¤è¤ëÄ´À°¤Î±Æ¶Á¤ò¼õ¤±¤Ê¤¤¡¢¥Ï¡¼¥É¥¦¥§¥¢¤Ë¤è¤ë
À¸¤Î»þ¹ï¤Ø¤Î¥¢¥¯¥»¥¹¤¬¤Ç¤­¤ë¡£
.TP
.B CLOCK_PROCESS_CPUTIME_ID
.\"O High-resolution per-process timer from the CPU.
CPU ¤Ë¤è¤ë¹âʬ²òǽ¤Î¥×¥í¥»¥¹Ëè¤Î¥¿¥¤¥Þ¡£
.TP
.B CLOCK_THREAD_CPUTIME_ID
.\"O Thread-specific CPU-time clock.
¥¹¥ì¥Ã¥É¸ÇÍ­¤Î CPU ¥¿¥¤¥à¥¯¥í¥Ã¥¯¡£
.\"O .SH "RETURN VALUE"
.SH ÊÖ¤êÃÍ
.\"O .BR clock_gettime (),
.\"O .BR clock_settime ()
.\"O and
.\"O .BR clock_getres ()
.\"O return 0 for success, or \-1 for failure (in which case
.\"O .I errno
.\"O is set appropriately).
.BR clock_gettime (),
.BR clock_settime (),
.BR clock_getres ()
¤ÏÀ®¸ù¤·¤¿¾ì¹ç¤Ë 0 ¤òÊÖ¤·¡¢¼ºÇÔ¤·¤¿¾ì¹ç¤Ë \-1 ¤òÊÖ¤¹
(¼ºÇÔ¤·¤¿¾ì¹ç¡¢
.I errno
¤¬Å¬ÀÚ¤ËÀßÄꤵ¤ì¤ë)¡£
.\"O .SH ERRORS
.SH ¥¨¥é¡¼
.TP
.B EFAULT
.\"O .I tp
.\"O points outside the accessible address space.
.I tp
¤¬¥¢¥¯¥»¥¹²Äǽ¤Ê¥¢¥É¥ì¥¹¶õ´Ö¤Î³°¤ò»Ø¤·¤¿¡£
.TP
.B EINVAL
.\"O The
.\"O .I clk_id
.\"O specified is not supported on this system.
.\" Linux also gives this error on attempts to set CLOCK_PROCESS_CPUTIME_ID
.\" and CLOCK_THREAD_CPUTIME_ID, when probably the proper error should be
.\" EPERM.
»ØÄꤵ¤ì¤¿
.I clk_id
¤¬¤³¤Î¥·¥¹¥Æ¥à¤Ç¥µ¥Ý¡¼¥È¤µ¤ì¤Æ¤¤¤Ê¤¤¡£
.TP
.B EPERM
.\"O .BR clock_settime ()
.\"O does not have permission to set the clock indicated.
»Ø¼¨¤µ¤ì¤¿¥¯¥í¥Ã¥¯¤òÀßÄꤹ¤ë¸¢¸Â¤¬
.BR clock_settime ()
¤Ë¤Ê¤¤¡£
.\"O .SH "CONFORMING TO"
.SH ½àµò
SUSv2, POSIX.1-2001.
.\"O .SH AVAILABILITY
.SH ²ÄÍÑÀ­
.\"O On POSIX systems on which these functions are available, the symbol
.\"O .B _POSIX_TIMERS
.\"O is defined in \fI<unistd.h>\fP to a value greater than 0.
¤³¤ì¤é¤Î´Ø¿ô¤¬ÍøÍѲÄǽ¤Ê POSIX ¥·¥¹¥Æ¥à¤Ç¤Ï¡¢\fI<unistd.h>\fP ¤Ë¤ª¤¤¤Æ¥·¥ó¥Ü¥ë
.B _POSIX_TIMERS
¤¬ 0 ¤è¤êÂ礭¤¤ÃͤËÄêµÁ¤µ¤ì¤Æ¤¤¤ë¡£
.\"O The symbols
.\"O .BR _POSIX_MONOTONIC_CLOCK ,
.\"O .BR _POSIX_CPUTIME ,
.\"O .B _POSIX_THREAD_CPUTIME
.\"O indicate that
.\"O .BR CLOCK_MONOTONIC ,
.\"O .BR CLOCK_PROCESS_CPUTIME_ID ,
.\"O .B CLOCK_THREAD_CPUTIME_ID
.\"O are available.
¥·¥ó¥Ü¥ë
.BR _POSIX_MONOTONIC_CLOCK ,
.BR _POSIX_CPUTIME ,
.B _POSIX_THREAD_CPUTIME
¤Ï
.BR CLOCK_MONOTONIC ,
.BR CLOCK_PROCESS_CPUTIME_ID ,
.B CLOCK_THREAD_CPUTIME_ID
¤¬ÍøÍѲÄǽ¤Ê¤³¤È¤ò¼¨¤¹¡£
.\"O (See also
.\"O .BR sysconf (3).)
.RB ( sysconf (3)
¤â»²¾È¤¹¤ë¤³¤È¡£)
.\"O .SH NOTES
.SH Ãí°Õ
.\"O .SS Note for SMP systems
.SS "SMP ¥·¥¹¥Æ¥à¤Ë¤Ä¤¤¤Æ¤ÎÃí°Õ"
.\"O The
.\"O .B CLOCK_PROCESS_CPUTIME_ID
.\"O and
.\"O .B CLOCK_THREAD_CPUTIME_ID
.\"O clocks are realized on many platforms using timers from the CPUs
.\"O (TSC on i386, AR.ITC on Itanium).
.B CLOCK_PROCESS_CPUTIME_ID
¤È
.B CLOCK_THREAD_CPUTIME_ID
¥¯¥í¥Ã¥¯¤Ï¡¢CPU ¤«¤é¤Î¥¿¥¤¥Þ
(i386 ¾å¤Î TSC¡¢Itanium ¾å¤Î AR.ITC) ¤òÍѤ¤¤Æ¼Â¸½¤µ¤ì¤Æ¤¤¤ë¡£
.\"O These registers may differ between CPUs and as a consequence
.\"O these clocks may return
.\"O .B bogus results
.\"O if a process is migrated to another CPU.
¤³¤ì¤é¤Î¥ì¥¸¥¹¥¿¤Ï CPU ´Ö¤Ç°Û¤Ê¤ë²ÄǽÀ­¤¬¤¢¤ê¡¢
¥×¥í¥»¥¹¤¬Â¾¤Î CPU ¤Ë°ÜÆ°¤µ¤»¤é¤ì¤¿¾ì¹ç¡¢
·ë²Ì¤È¤·¤Æ¤³¤ì¤é¤Î¥¯¥í¥Ã¥¯¤¬\fBµ¶¤Î·ë²Ì\fR
(bogus results) ¤òÊÖ¤¹¤«¤â¤·¤ì¤Ê¤¤¡£
.PP
.\"O If the CPUs in an SMP system have different clock sources then
.\"O there is no way to maintain a correlation between the timer registers since
.\"O each CPU will run at a slightly different frequency.
.\"O If that is the case then
.\"O .I clock_getcpuclockid(0)
.\"O will return
.\"O .B ENOENT
.\"O to signify this condition.
.\"O The two clocks will then only be useful if it
.\"O can be ensured that a process stays on a certain CPU.
SMP ¥·¥¹¥Æ¥à¤Î³Æ CPU ¤¬ÊÌ¡¹¤Î¥¯¥í¥Ã¥¯¸»¤ò»ý¤Ä¾ì¹ç¡¢
¥¿¥¤¥Þ¥ì¥¸¥¹¥¿´Ö¤ÎÁê¸ß´Ø·¸¤ò´ÉÍý¤¹¤ëÊýË¡¤Ï¤Ê¤¤¡£
¤³¤ì¤Ï³Æ CPU ¤¬Èù̯¤Ë°Û¤Ê¤ë¼þÇÈ¿ô¤ÇÆ°ºî¤¹¤ë¤¿¤á¤Ç¤¢¤ë¡£
¤³¤ì¤¬¿¿¼Â¤Î¾ì¹ç (ÌõÃð: ³Æ CPU ¤¬ÊÌ¡¹¤Î¥¯¥í¥Ã¥¯¸»¤ò»ý¤Ä¾ì¹ç)¡¢
.I clock_getcpuclockid(0)
¤Ï
.B ENOENT
¤òÊÖ¤·¤Æ¡¢¤½¤Î¾õ¶·¤òɽ¤¹¡£
2 ¤Ä¤Î¥¯¥í¥Ã¥¯¤Ï¡¢¥×¥í¥»¥¹¤¬ÆÃÄê¤Î CPU ¾å¤Ëα¤Þ¤Ã¤Æ¤¤¤ë¤³¤È¤¬
ÊݾڤǤ­¤ë¾ì¹ç¤Ë¤Î¤ßÍ­¸ú¤Ç¤¢¤ë¡£
.PP
.\"O The processors in an SMP system do not start all at exactly the same
.\"O time and therefore the timer registers are typically running at an offset.
SMP ¥·¥¹¥Æ¥à¤Î³Æ¥×¥í¥»¥Ã¥µ¤ÏÁ´¤¯Æ±¤¸»þ¹ï¤Ëµ¯Æ°¤¹¤ëÌõ¤Ç¤Ï¤Ê¤¤¤Î¤Ç¡¢
³Æ¥¿¥¤¥Þ¥ì¥¸¥¹¥¿¤ÏÄ̾ï¤Ï¤¢¤ë¥ª¥Õ¥»¥Ã¥È¤ÇÆ°ºî¤·¤Æ¤¤¤ë¡£
.\"O Some architectures include code that attempts to limit these offsets on bootup.
¥ª¥Õ¥»¥Ã¥È¤ò¥Ö¡¼¥È»þ¤ËÀ©¸Â¤¹¤ë¥³¡¼¥É¤¬´Þ¤Þ¤ì¤ë¥¢¡¼¥­¥Æ¥¯¥Á¥ã¤â¤¢¤ë¡£
.\"O However, the code cannot guarantee to accurately tune the offsets.
¤·¤«¤·¡¢¤³¤Î¥³¡¼¥É¤¬¥ª¥Õ¥»¥Ã¥È¤òÀµ³Î¤ËÄ´À°¤¹¤ë¤³¤È¤ÏÊݾڤǤ­¤Ê¤¤¡£
.\"O Glibc contains no provisions to deal with these offsets (unlike the Linux
.\"O Kernel).
.\"O Typically these offsets are small and therefore the effects may be
.\"O negligible in most cases.
glibc ¤Ï (Linux ¥«¡¼¥Í¥ë¤È¤Ï°Û¤Ê¤ê) ¥ª¥Õ¥»¥Ã¥È¤ò°·¤¦¤¿¤á¤Î¥³¡¼¥É¤òÄ󶡤·¤Ê¤¤¡£
Ä̾ï¤Ï¤³¤ì¤é¤Î¥ª¥Õ¥»¥Ã¥È¤¬¾®¤µ¤¤¤Î¤Ç¡¢Â¿¤¯¤Î¾ì¹ç¤Ç¤½¤Î±Æ¶Á¤Ï̵»ë¤Ç¤­¤ë¡£
.\"O .SH BUGS
.SH ¥Ð¥°
.\"O According to POSIX.1-2001, a process with "appropriate privileges" may set the
.\"O .B CLOCK_PROCESS_CPUTIME_ID
.\"O and
.\"O .B CLOCK_THREAD_CPUTIME_ID
.\"O clocks using
.\"O .BR clock_settime ().
.\"O On Linux, these clocks are not settable
.\"O (i.e., no process has "appropriate privileges").
POSIX.1-2001 ¤Ç¤Ï¡¢
¡ÖŬÀÚ¤ÊÆø¢ (appropriate privileges)¡×¤ò»ý¤Ã¤¿¥×¥í¥»¥¹¤Ï¡¢
.BR clock_settime ()
¤ò»È¤Ã¤Æ¡¢¥¯¥í¥Ã¥¯
.B CLOCK_PROCESS_CPUTIME_ID
¤È
.B CLOCK_THREAD_CPUTIME_ID
¤òÀßÄꤹ¤ë¤³¤È¤¬¤Ç¤­¤ë¤È¤µ¤ì¤Æ¤¤¤ë¡£
Linux ¤Ç¤Ï¡¢¤³¤ì¤é¤Î¥¯¥í¥Ã¥¯¤ÏÀßÄê²Äǽ¤Ç¤Ï¤Ê¤¤
(¤¹¤Ê¤ï¤Á¡¢¤É¤Î¥×¥í¥»¥¹¤â¡ÖŬÀÚ¤ÊÆø¢¡×¤ò»ý¤¿¤Ê¤¤)¡£
.\" See http://bugzilla.kernel.org/show_bug.cgi?id=11972
.\"O .SH "SEE ALSO"
.SH ´ØÏ¢¹àÌÜ
.BR date (1),
.BR adjtimex (2),
.BR gettimeofday (2),
.BR settimeofday (2),
.BR time (2),
.BR clock_getcpuclockid (3),
.BR ctime (3),
.BR ftime (3),
.BR pthread_getcpuclockid (3),
.BR sysconf (3),
.BR time (7)