2004-11-03 13:51:07 +00:00
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.\" Copyright 7/93 by Darren Senn <sinster@scintilla.santa-clara.ca.us>
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2016-07-05 08:53:49 +00:00
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.\" and Copyright (C) 2016, Michael Kerrisk <mtk.manpages@gmail.com>
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2004-11-03 13:51:07 +00:00
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.\" Based on a similar page Copyright 1992 by Rick Faith
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ldd.1, capget.2, clone.2, create_module.2, fallocate.2, futex.2, get_kernel_syms.2, get_thread_area.2, getcpu.2, getitimer.2, getpid.2, io_cancel.2, io_destroy.2, io_getevents.2, io_setup.2, io_submit.2, ioctl_list.2, mkdir.2, mknod.2, pciconfig_read.2, pivot_root.2, posix_fadvise.2, query_module.2, sendfile.2, set_thread_area.2, setns.2, unshare.2, __setfpucw.3, a64l.3, addseverity.3, argz_add.3, bindresvport.3, cabs.3, cacos.3, cacosh.3, canonicalize_file_name.3, carg.3, casin.3, casinh.3, catan.3, catanh.3, ccos.3, ccosh.3, cerf.3, cexp.3, cexp2.3, cimag.3, clog.3, clog10.3, clog2.3, cmsg.3, conj.3, cpow.3, cproj.3, creal.3, csin.3, csinh.3, csqrt.3, ctan.3, ctanh.3, des_crypt.3, envz_add.3, fdim.3, fma.3, fmax.3, fmemopen.3, fmin.3, fmtmsg.3, fpclassify.3, gamma.3, getpt.3, getrpcent.3, getrpcport.3, getttyent.3, isgreater.3, key_setsecret.3, lgamma.3, malloc_hook.3, mempcpy.3, nan.3, netlink.3, nextafter.3, putgrent.3, remove.3, remquo.3, rpc.3, rtime.3, rtnetlink.3, setaliasent.3, setnetgrent.3, signbit.3, significand.3, sincos.3, stdin.3, tgamma.3, xcrypt.3, xdr.3, cciss.4, hpsa.4, mouse.4, pts.4, sk98lin.4, tty_ioctl.4, wavelan.4, hosts.equiv.5, rpc.5, tzfile.5, boot.7, complex.7, ddp.7, fifo.7, futex.7, icmp.7, ip.7, ipv6.7, netdevice.7, netlink.7, packet.7, raw.7, rtnetlink.7, socket.7, tcp.7, udp.7, unix.7, x25.7, sync.8: Global fix: Put copyright info at top of page, followed by blank line and LICENSE
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2013-03-10 09:29:51 +00:00
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.\"
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2013-03-10 09:29:11 +00:00
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.\" %%%LICENSE_START(FREELY_REDISTRIBUTABLE)
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2016-07-05 08:54:44 +00:00
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.\" May be freely distributed and modified
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epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, fallocate.2, futex.2, getcpu.2, getitimer.2, ioctl_list.2, ioprio_set.2, migrate_pages.2, move_pages.2, pciconfig_read.2, sendfile.2, setns.2, signalfd.2, spu_create.2, spu_run.2, sysinfo.2, timerfd_create.2, backtrace.3, cmsg.3, error.3, getpt.3, getrpcent.3, getrpcport.3, getsubopt.3, offsetof.3, program_invocation_name.3, rpc.3, rpmatch.3, rtnetlink.3, xdr.3, cciss.4, hpsa.4, pts.4, charmap.5, dir_colors.5, elf.5, gai.conf.5, locale.5, nscd.conf.5, nss.5, resolv.conf.5, rpc.5, arp.7, cpuset.7, ddp.7, epoll.7, fifo.7, futex.7, icmp.7, ip.7, ipv6.7, mailaddr.7, netdevice.7, packet.7, raw.7, regex.7, rtnetlink.7, socket.7, spufs.7, tcp.7, udp.7, unix.7, x25.7, ldconfig.8, nscd.8: Global fix: s/END_LICENSE/LICENSE_END/
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2013-03-12 09:26:07 +00:00
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.\" %%%LICENSE_END
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2013-03-12 10:59:08 +00:00
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.\"
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2004-11-03 13:51:07 +00:00
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.\" Modified Tue Oct 22 00:22:35 EDT 1996 by Eric S. Raymond <esr@thyrsus.com>
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2005-04-06 15:29:32 +00:00
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.\" 2005-04-06 mtk, Matthias Lang <matthias@corelatus.se>
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.\" Noted MAX_SEC_IN_JIFFIES ceiling
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ldd.1, arch_prctl.2, faccessat.2, fchmodat.2, fchownat.2, flock.2, futimesat.2, getcpu.2, getdents.2, getitimer.2, getpid.2, getresuid.2, getunwind.2, kexec_load.2, mkdirat.2, mknodat.2, openat.2, outb.2, perfmonctl.2, readlinkat.2, renameat.2, symlinkat.2, timer_delete.2, timer_getoverrun.2, timer_settime.2, unlinkat.2: srcfix
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2013-03-12 11:35:04 +00:00
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.\"
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ldd.1, localedef.1, add_key.2, chroot.2, clone.2, fork.2, futex.2, get_mempolicy.2, get_robust_list.2, getitimer.2, getpriority.2, ioctl.2, ioctl_ficlonerange.2, ioctl_fideduperange.2, kcmp.2, kill.2, lookup_dcookie.2, mmap.2, mount.2, open.2, pciconfig_read.2, perf_event_open.2, prctl.2, process_vm_readv.2, ptrace.2, quotactl.2, recv.2, setfsgid.2, setfsuid.2, sysinfo.2, umask.2, umount.2, unshare.2, utimensat.2, wait.2, assert.3, fmax.3, fmin.3, getauxval.3, inet_pton.3, malloc_hook.3, memmem.3, mkdtemp.3, mktemp.3, printf.3, strcasecmp.3, strcat.3, strtoul.3, strxfrm.3, console_codes.4, console_ioctl.4, lirc.4, tty.4, vcs.4, charmap.5, elf.5, locale.5, proc.5, repertoiremap.5, utmp.5, capabilities.7, cgroup_namespaces.7, cgroups.7, charsets.7, cp1251.7, cp1252.7, credentials.7, feature_test_macros.7, iso_8859-1.7, iso_8859-15.7, iso_8859-5.7, koi8-r.7, koi8-u.7, man-pages.7, mount_namespaces.7, namespaces.7, netlink.7, pid_namespaces.7, unix.7, user_namespaces.7, utf-8.7: tstamp
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2016-07-17 16:07:58 +00:00
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.TH GETITIMER 2 2016-07-17 "Linux" "Linux Programmer's Manual"
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2004-11-03 13:51:07 +00:00
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.SH NAME
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getitimer, setitimer \- get or set value of an interval timer
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.SH SYNOPSIS
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2006-03-08 02:48:53 +00:00
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.nf
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2004-11-03 13:51:07 +00:00
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.B #include <sys/time.h>
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.sp
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2009-02-09 23:37:42 +00:00
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.BI "int getitimer(int " which ", struct itimerval *" curr_value );
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2006-03-08 02:48:53 +00:00
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.br
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2009-02-09 23:37:42 +00:00
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.BI "int setitimer(int " which ", const struct itimerval *" new_value ,
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.BI " struct itimerval *" old_value );
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2006-03-08 02:48:53 +00:00
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.fi
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2004-11-03 13:51:07 +00:00
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.SH DESCRIPTION
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2016-07-05 08:53:49 +00:00
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These system calls provide access to interval timers, that is,
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timers that initially expire at some point in the future,
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and (optionally) at regular intervals after that.
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When a timer expires, a signal is generated for the calling process,
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and the timer is reset to the specified interval
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(if the interval is nonzero).
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Three types of timers\(emspecified via the
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.IR which
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argument\(emare provided,
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each of which counts against a different clock and
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generates a different signal on timer expiration:
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2004-11-03 13:51:07 +00:00
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.TP 1.5i
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.B ITIMER_REAL
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2016-07-05 08:53:49 +00:00
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This timer counts down in real (i.e., wall clock) time.
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At each expiration, a
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2004-11-03 13:51:07 +00:00
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.B SIGALRM
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2016-07-05 08:53:49 +00:00
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signal is generated.
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2004-11-03 13:51:07 +00:00
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.TP
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.B ITIMER_VIRTUAL
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2016-07-05 08:53:49 +00:00
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This timer counts down against the user-mode CPU time consumed by the process.
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(The measurement includes CPU time consumed by all threads in the process.)
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At each expiration, a
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2004-11-03 13:51:07 +00:00
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.B SIGVTALRM
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2016-07-05 08:53:49 +00:00
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signal is generated.
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2004-11-03 13:51:07 +00:00
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.TP
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.B ITIMER_PROF
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2016-07-05 08:53:49 +00:00
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This timer counts down against the total (i.e., both user and system)
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CPU time consumed by the process.
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(The measurement includes CPU time consumed by all threads in the process.)
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At each expiration, a
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2004-11-03 13:51:07 +00:00
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.B SIGPROF
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2016-07-05 08:53:49 +00:00
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signal is generated.
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In conjunction with
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.BR ITIMER_VIRTUAL ,
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this timer can be used to profile user and system CPU time
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consumed by the process.
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2004-11-03 13:51:07 +00:00
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.LP
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2016-07-05 08:53:49 +00:00
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A process has only one of each of the three types of timers.
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2004-11-03 13:51:07 +00:00
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Timer values are defined by the following structures:
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.PD 0
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2007-12-23 14:14:04 +00:00
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.in +4n
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2004-11-03 13:51:07 +00:00
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.nf
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Salut Olivier (and Nishanth),
Regarding man page documentation of the problem of short sleeps
for setiteimer(2)...
> > -- pointers to those threads
>
> http://bugzilla.kernel.org/show_bug.cgi?id=4569
> http://lkml.org/lkml/2005/4/29/163
>
> > -- indications of which kernel versions show this bahaviour
>
> AFAIK, all versions as far as x86 is concerned.
> Dunno if it is hardware specific.
>
> > -- a (short) test program to demonstrate it, if you have one.
>
> See the bugzilla bug's attachments
Sorry for the long delay in following this up, but I've got to
it now. I tweaked your suggestions slightly:
{{
Timers will never expire before the requested time,
-instead expiring some short, constant time afterwards, dependent
-on the system timer resolution (currently 10ms).
+but may expire some (short) time afterwards, which depends
+on the system timer resolution and on the system load.
+Upon expiration, a signal will be generated and the timer reset.
+If the timer expires while the process is active (always true for
+On certain systems (including x86), the Linux kernel has a bug which will
+produce premature timer expirations of up to one jiffy under some
+circumstances.
}}
Thanks for this bug reporet,
Nishanth: if and when your changes are accepted, and the problem
is thus fixed, could you please send me a notification of that
fact, and I can then further amend the manual pages.
Cheers,
Michael
/* itimer_short_interval_bug.c
June 2005
In current Linux kernels, an interval timer set using setitimer()
can sometimes sleep *less* than the specified interval.
This program demonstrates the behaviour by looping through all
itimer values from 1 microsecond upwards, in one microsecond steps.
*/
/* Adapted from a program by Olivier Croquette, June 2005 */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/wait.h>
typedef unsigned long long int u_time_t; /* in microsecs */
static int handler_flag;
/* return time as a number of microsecs */
static u_time_t
gettime(void )
{
struct timeval tv;
if ( gettimeofday(&tv, NULL) == -1) {
perror("gettimeofday()");
return 0;
}
return (tv.tv_usec + tv.tv_sec * 1000000LL);
}
static void
handler (int sig, siginfo_t *siginfo, void *context)
{
handler_flag++;
return ;
}
/* Sleep for 'time' microsecs. */
static int
isleep(u_time_t time)
{
struct itimerval newtv;
sigset_t sigset;
struct sigaction sigact;
if (time == 0)
return 0;
/* block SIGALRM */
sigemptyset (&sigset);
sigaddset (&sigset, SIGALRM);
sigprocmask (SIG_BLOCK, &sigset, NULL);
/* set up our handler */
sigact.sa_sigaction = handler;
sigemptyset(&sigact.sa_mask);
sigact.sa_flags = SA_SIGINFO;
sigaction (SIGALRM, &sigact, NULL);
newtv.it_interval.tv_sec = 0;
newtv.it_interval.tv_usec = 0;
newtv.it_value.tv_sec = time / 1000000;
newtv.it_value.tv_usec = time % 1000000;
if (setitimer(ITIMER_REAL,&newtv,NULL) == -1) {
perror("setitimer(set)");
return 1;
}
sigemptyset (&sigset);
sigsuspend (&sigset);
return 0;
}
int
main(int argc, char *argv[]) {
u_time_t wait;
int loop, numLoops;
u_time_t t1, t2;
u_time_t actual;
long long minDiff, maxDiff, totDiff, diff;
int numFail = 0;
if (argc != 2) {
fprintf(stderr, "Usage: %s num-loops\n", argv[0]);
exit(EXIT_FAILURE);
} /* if */
numLoops = atoi(argv[1]);
setbuf(stdout, NULL);
for (wait = 1; ; wait++) {
maxDiff = 0;
numFail = 0;
totDiff = 0;
minDiff = -wait;
if (wait % 10000 == 0)
printf("%llu\n", wait);
for (loop = 0; loop < numLoops; loop++) {
t1 = gettime();
handler_flag = 0;
isleep(wait);
if ( handler_flag != 1 )
printf("Problem with the handler flag (%d)!\n", handler_flag);
t2 = gettime();
actual = t2 - t1;
if ( actual < wait ) {
diff = actual - wait;
if (diff < maxDiff)
maxDiff = diff;
if (diff > minDiff)
minDiff = diff;
totDiff += diff;
numFail++;
} /* if */
} /* for */
if (numFail > 0)
printf("%llu: %3d fail (%4lld %4lld; avg=%6.1f)\n",
wait, numFail, minDiff, maxDiff,
(double) totDiff / numFail);
} /* for */
return 0;
} /* main */
2005-06-13 09:01:49 +00:00
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2004-11-03 13:51:07 +00:00
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struct itimerval {
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2014-07-01 07:36:28 +00:00
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struct timeval it_interval; /* Interval for periodic timer */
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struct timeval it_value; /* Time until next expiration */
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2004-11-03 13:51:07 +00:00
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};
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2007-12-23 14:14:04 +00:00
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2004-11-03 13:51:07 +00:00
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struct timeval {
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2012-09-30 05:39:56 +00:00
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time_t tv_sec; /* seconds */
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suseconds_t tv_usec; /* microseconds */
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2004-11-03 13:51:07 +00:00
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};
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.fi
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2007-12-23 14:14:04 +00:00
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.in
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2004-11-03 13:51:07 +00:00
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.PD
|
2016-07-05 08:53:49 +00:00
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.SS getitimer()
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2004-11-03 13:51:07 +00:00
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The function
|
2005-06-23 07:16:55 +00:00
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.BR getitimer ()
|
2016-07-24 13:13:25 +00:00
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places the current value of the timer specified by
|
2016-07-05 08:53:49 +00:00
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.IR which
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in the buffer pointed to by
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.IR curr_value .
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2014-07-01 07:36:28 +00:00
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The
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2016-07-05 08:53:49 +00:00
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.IR it_value
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substructure is populated with the amount of time remaining until
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the next expiration of the specified timer.
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This value changes as the timer counts down, and will be reset to
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.IR it_interval
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when the timer expires.
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If both fields of
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.IR it_value
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are zero, then this timer is currently disarmed (inactive).
|
2009-02-09 23:37:42 +00:00
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2016-07-05 08:53:49 +00:00
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The
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.IR it_interval
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substructure is populated with the timer interval.
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If both fields of
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.IR it_interval
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are zero, then this is a single-shot timer (i.e., it expires just once).
|
2016-07-24 12:46:11 +00:00
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.SS setitimer()
|
2004-11-03 13:51:07 +00:00
|
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The function
|
2005-06-23 07:16:55 +00:00
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.BR setitimer ()
|
2016-07-05 08:53:49 +00:00
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arms or disarms the timer specified by
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.IR which ,
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by setting the timer to the value specified by
|
2009-02-09 23:37:42 +00:00
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.IR new_value .
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2004-11-03 13:51:07 +00:00
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If
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2009-02-09 23:37:42 +00:00
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.I old_value
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2016-07-05 08:53:49 +00:00
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is non-NULL,
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the buffer it points to is used to return the previous value of the timer
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(i.e., the same information that is returned by
|
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.BR getitimer ()).
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If either field in
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.IR new_value.it_value
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is nonzero,
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then the timer is armed to initially expire at the specified time.
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If both fields in
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.IR new_value.it_value
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are zero, then the timer is disarmed.
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The
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.IR new_value.it_interval
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field specifies the new interval for the timer;
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if both of its subfields are zero, the timer is single-shot.
|
getent.1, intro.1, time.1, _exit.2, _syscall.2, accept.2, access.2, acct.2, adjtimex.2, alarm.2, alloc_hugepages.2, arch_prctl.2, bdflush.2, bind.2, brk.2, cacheflush.2, capget.2, chdir.2, chmod.2, chown.2, chroot.2, clock_getres.2, clock_nanosleep.2, clone.2, close.2, connect.2, create_module.2, delete_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, exit_group.2, faccessat.2, fchmodat.2, fchownat.2, fcntl.2, flock.2, fork.2, fstatat.2, fsync.2, futex.2, futimesat.2, get_kernel_syms.2, get_robust_list.2, get_thread_area.2, getcpu.2, getdents.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpid.2, getpriority.2, getresuid.2, getrlimit.2, getrusage.2, getsid.2, getsockname.2, getsockopt.2, gettid.2, gettimeofday.2, getuid.2, getunwind.2, getxattr.2, idle.2, init_module.2, inotify_add_watch.2, inotify_init.2, inotify_rm_watch.2, intro.2, io_cancel.2, io_destroy.2, io_getevents.2, io_setup.2, io_submit.2, ioctl.2, ioctl_list.2, ioperm.2, iopl.2, ioprio_set.2, ipc.2, kcmp.2, kill.2, killpg.2, link.2, linkat.2, listen.2, listxattr.2, llseek.2, lookup_dcookie.2, lseek.2, madvise.2, migrate_pages.2, mincore.2, mkdir.2, mkdirat.2, mknod.2, mknodat.2, mlock.2, mmap.2, mmap2.2, modify_ldt.2, mount.2, move_pages.2, mprotect.2, mq_getsetattr.2, mremap.2, msgctl.2, msgget.2, msgop.2, msync.2, nanosleep.2, nfsservctl.2, nice.2, open.2, openat.2, outb.2, pause.2, pciconfig_read.2, perf_event_open.2, perfmonctl.2, personality.2, pipe.2, pivot_root.2, poll.2, posix_fadvise.2, prctl.2, pread.2, process_vm_readv.2, ptrace.2, query_module.2, quotactl.2, read.2, readahead.2, readdir.2, readlink.2, readlinkat.2, readv.2, reboot.2, recv.2, remap_file_pages.2, removexattr.2, rename.2, renameat.2, rmdir.2, rt_sigqueueinfo.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, select.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, set_thread_area.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, setup.2, setxattr.2, shmctl.2, shmget.2, shmop.2, shutdown.2, sigaction.2, sigaltstack.2, signal.2, signalfd.2, sigpending.2, sigprocmask.2, sigreturn.2, sigsuspend.2, sigwaitinfo.2, socket.2, socketcall.2, socketpair.2, splice.2, stat.2, statfs.2, stime.2, swapon.2, symlink.2, symlinkat.2, sync.2, sync_file_range.2, sysctl.2, sysfs.2, sysinfo.2, syslog.2, tee.2, time.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, uname.2, unimplemented.2, unlink.2, unlinkat.2, uselib.2, ustat.2, utime.2, utimensat.2, vfork.2, vhangup.2, vm86.2, vmsplice.2, wait.2, wait4.2, write.2, CPU_SET.3, INFINITY.3, MB_CUR_MAX.3, MB_LEN_MAX.3, __setfpucw.3, a64l.3, abort.3, abs.3, acos.3, acosh.3, addseverity.3, adjtime.3, aio_cancel.3, aio_error.3, aio_fsync.3, aio_read.3, aio_return.3, aio_suspend.3, aio_write.3, alloca.3, argz_add.3, asin.3, asinh.3, asprintf.3, assert.3, assert_perror.3, atan.3, atan2.3, atanh.3, atexit.3, atof.3, atoi.3, backtrace.3, basename.3, bcmp.3, bcopy.3, bindresvport.3, bsd_signal.3, bsearch.3, bstring.3, btowc.3, btree.3, byteorder.3, bzero.3, cabs.3, cacos.3, cacosh.3, canonicalize_file_name.3, carg.3, casin.3, casinh.3, catan.3, catanh.3, catgets.3, catopen.3, cbrt.3, ccos.3, ccosh.3, ceil.3, cerf.3, cexp.3, cexp2.3, cfree.3, cimag.3, clearenv.3, clock.3, clock_getcpuclockid.3, clog.3, clog10.3, clog2.3, closedir.3, cmsg.3, confstr.3, conj.3, copysign.3, cos.3, cosh.3, cpow.3, cproj.3, creal.3, crypt.3, csin.3, csinh.3, csqrt.3, ctan.3, ctanh.3, ctermid.3, ctime.3, daemon.3, dbopen.3, des_crypt.3, difftime.3, dirfd.3, div.3, dl_iterate_phdr.3, dlopen.3, dprintf.3, drand48.3, drand48_r.3, dysize.3, ecvt.3, ecvt_r.3, encrypt.3, end.3, endian.3, envz_add.3, erf.3, erfc.3, err.3, errno.3, error.3, ether_aton.3, euidaccess.3, exec.3, exit.3, exp.3, exp10.3, exp2.3, expm1.3, fabs.3, fclose.3, fcloseall.3, fdim.3, fenv.3, ferror.3, fexecve.3, fflush.3, ffs.3, fgetgrent.3, fgetpwent.3, fgetwc.3, fgetws.3, finite.3, flockfile.3, floor.3, fma.3, fmax.3, fmemopen.3, fmin.3, fmod.3, fmtmsg.3, fnmatch.3, fopen.3, fpathconf.3, fpclassify.3, fpurge.3, fputwc.3, fputws.3, fread.3, frexp.3, fseek.3, fseeko.3, ftime.3, ftok.3, fts.3, ftw.3, futimes.3, fwide.3, gamma.3, gcvt.3, getaddrinfo.3, getaddrinfo_a.3, getauxval.3, getcontext.3, getcwd.3, getdate.3, getdirentries.3, getdtablesize.3, getenv.3, getfsent.3, getgrent.3, getgrent_r.3, getgrnam.3, getgrouplist.3, gethostbyname.3, gethostid.3, getipnodebyname.3, getline.3, getloadavg.3, getlogin.3, getmntent.3, getnameinfo.3, getnetent.3, getnetent_r.3, getopt.3, getpass.3, getprotoent.3, getprotoent_r.3, getpt.3, getpw.3, getpwent.3, getpwent_r.3, getpwnam.3, getrpcent.3, getrpcent_r.3, getrpcport.3, gets.3, getservent.3, getservent_r.3, getspnam.3, getttyent.3, getumask.3, getusershell.3, getutent.3, getw.3, getwchar.3, glob.3, grantpt.3, gsignal.3, hash.3, hsearch.3, hypot.3, iconv.3, iconv_close.3, iconv_open.3, ilogb.3, index.3, inet.3, inet_ntop.3, inet_pton.3, infnan.3, initgroups.3, insque.3, intro.3, isalpha.3, isatty.3, isgreater.3, iswalnum.3, iswalpha.3, iswblank.3, iswcntrl.3, iswctype.3, iswdigit.3, iswgraph.3, iswlower.3, iswprint.3, iswpunct.3, iswspace.3, iswupper.3, iswxdigit.3, j0.3, key_setsecret.3, ldexp.3, lgamma.3, lio_listio.3, localeconv.3, lockf.3, log.3, log10.3, log1p.3, log2.3, logb.3, login.3, longjmp.3, lrint.3, lround.3, lsearch.3, lseek64.3, makecontext.3, makedev.3, malloc.3, malloc_hook.3, mblen.3, mbrlen.3, mbrtowc.3, mbsinit.3, mbsnrtowcs.3, mbsrtowcs.3, mbstowcs.3, mbtowc.3, memccpy.3, memchr.3, memcmp.3, memcpy.3, memfrob.3, memmem.3, memmove.3, mempcpy.3, memset.3, mkdtemp.3, mkfifo.3, mkfifoat.3, mkstemp.3, mktemp.3, modf.3, mpool.3, mq_close.3, mq_getattr.3, mq_notify.3, mq_open.3, mq_receive.3, mq_send.3, mq_unlink.3, mtrace.3, nan.3, netlink.3, nextafter.3, nl_langinfo.3, offsetof.3, on_exit.3, opendir.3, openpty.3, perror.3, popen.3, posix_fallocate.3, posix_memalign.3, posix_openpt.3, pow.3, pow10.3, printf.3, profil.3, program_invocation_name.3, psignal.3, pthread_kill_other_threads_np.3, ptsname.3, putenv.3, putgrent.3, putpwent.3, puts.3, putwchar.3, qecvt.3, qsort.3, queue.3, raise.3, rand.3, random.3, random_r.3, rcmd.3, re_comp.3, readdir.3, realpath.3, recno.3, regex.3, remainder.3, remove.3, remquo.3, resolver.3, rewinddir.3, rexec.3, rint.3, round.3, rpc.3, rpmatch.3, rtime.3, rtnetlink.3, scalb.3, scalbln.3, scandir.3, scandirat.3, scanf.3, seekdir.3, sem_close.3, sem_destroy.3, sem_getvalue.3, sem_init.3, sem_open.3, sem_post.3, sem_unlink.3, sem_wait.3, setaliasent.3, setbuf.3, setenv.3, setjmp.3, setlocale.3, setlogmask.3, setnetgrent.3, shm_open.3, siginterrupt.3, signbit.3, significand.3, sigpause.3, sigqueue.3, sigset.3, sigsetops.3, sigvec.3, sin.3, sincos.3, sinh.3, sleep.3, sockatmark.3, sqrt.3, statvfs.3, stdarg.3, stdin.3, stdio.3, stdio_ext.3, stpcpy.3, stpncpy.3, strcasecmp.3, strcat.3, strchr.3, strcmp.3, strcoll.3, strcpy.3, strdup.3, strerror.3, strfmon.3, strfry.3, strftime.3, string.3, strlen.3, strnlen.3, strpbrk.3, strptime.3, strsep.3, strsignal.3, strspn.3, strstr.3, strtod.3, strtoimax.3, strtok.3, strtol.3, strtoul.3, strverscmp.3, strxfrm.3, swab.3, sysconf.3, syslog.3, system.3, sysv_signal.3, tan.3, tanh.3, tcgetpgrp.3, tcgetsid.3, telldir.3, tempnam.3, termios.3, tgamma.3, timegm.3, timeradd.3, tmpfile.3, tmpnam.3, toascii.3, toupper.3, towctrans.3, towlower.3, towupper.3, trunc.3, tsearch.3, ttyname.3, ttyslot.3, tzset.3, ualarm.3, ulimit.3, ungetwc.3, unlocked_stdio.3, unlockpt.3, updwtmp.3, usleep.3, wcpcpy.3, wcpncpy.3, wcrtomb.3, wcscasecmp.3, wcscat.3, wcschr.3, wcscmp.3, wcscpy.3, wcscspn.3, wcsdup.3, wcslen.3, wcsncasecmp.3, wcsncat.3, wcsncmp.3, wcsncpy.3, wcsnlen.3, wcsnrtombs.3, wcspbrk.3, wcsrchr.3, wcsrtombs.3, wcsspn.3, wcsstr.3, wcstoimax.3, wcstok.3, wcstombs.3, wcswidth.3, wctob.3, wctomb.3, wctrans.3, wctype.3, wcwidth.3, wmemchr.3, wmemcmp.3, wmemcpy.3, wmemmove.3, wmemset.3, wordexp.3, wprintf.3, xcrypt.3, xdr.3, y0.3, cciss.4, console.4, console_codes.4, console_ioctl.4, dsp56k.4, fd.4, full.4, hd.4, hpsa.4, initrd.4, intro.4, lp.4, mem.4, mouse.4, null.4, pts.4, ram.4, random.4, rtc.4, sk98lin.4, st.4, tty.4, ttyS.4, tty_ioctl.4, vcs.4, wavelan.4, acct.5, charmap.5, dir_colors.5, filesystems.5, ftpusers.5, group.5, host.conf.5, hosts.5, hosts.equiv.5, intro.5, issue.5, locale.5, motd.5, networks.5, nologin.5, nscd.conf.5, passwd.5, proc.5, protocols.5, resolv.conf.5, rpc.5, securetty.5, services.5, shells.5, termcap.5, ttytype.5, utmp.5, armscii-8.7, arp.7, ascii.7, bootparam.7, capabilities.7, charsets.7, complex.7, cp1251.7, credentials.7, ddp.7, environ.7, epoll.7, fifo.7, futex.7, glob.7, hier.7, icmp.7, inotify.7, intro.7, ip.7, ipv6.7, iso_8859-1.7, iso_8859-10.7, iso_8859-11.7, iso_8859-13.7, iso_8859-14.7, iso_8859-15.7, iso_8859-16.7, iso_8859-2.7, iso_8859-3.7, iso_8859-4.7, iso_8859-5.7, iso_8859-6.7, iso_8859-7.7, iso_8859-8.7, iso_8859-9.7, koi8-r.7, koi8-u.7, locale.7, mailaddr.7, man.7, mq_overview.7, netdevice.7, netlink.7, numa.7, packet.7, path_resolution.7, pipe.7, posixoptions.7, pthreads.7, pty.7, raw.7, regex.7, rtld-audit.7, rtnetlink.7, sem_overview.7, shm_overview.7, sigevent.7, signal.7, socket.7, standards.7, suffixes.7, svipc.7, tcp.7, termio.7, time.7, udp.7, udplite.7, unicode.7, unix.7, uri.7, utf-8.7, x25.7, nscd.8, sync.8, tzselect.8, zdump.8, zic.8: Global fix: remove unneeded double quotes in .SH headings
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2013-02-24 18:01:36 +00:00
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.SH RETURN VALUE
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2007-04-12 22:42:49 +00:00
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On success, zero is returned.
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On error, \-1 is returned, and
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2004-11-03 13:51:07 +00:00
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.I errno
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is set appropriately.
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.SH ERRORS
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.TP
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.B EFAULT
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2009-02-09 23:37:42 +00:00
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.IR new_value ,
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.IR old_value ,
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2004-11-03 13:51:07 +00:00
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or
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2009-02-09 23:37:42 +00:00
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.I curr_value
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is not valid a pointer.
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2004-11-03 13:51:07 +00:00
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.TP
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.B EINVAL
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.I which
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is not one of
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.BR ITIMER_REAL ,
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2006-03-20 00:52:31 +00:00
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.BR ITIMER_VIRTUAL ,
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2004-11-03 13:51:07 +00:00
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or
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2007-08-28 13:15:35 +00:00
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.BR ITIMER_PROF ;
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2008-05-07 13:33:52 +00:00
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or (since Linux 2.6.22) one of the
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2007-08-28 13:15:35 +00:00
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.I tv_usec
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2009-02-09 23:37:42 +00:00
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fields in the structure pointed to by
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.I new_value
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contains a value outside the range 0 to 999999.
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getent.1, intro.1, time.1, _exit.2, _syscall.2, accept.2, access.2, acct.2, adjtimex.2, alarm.2, alloc_hugepages.2, arch_prctl.2, bdflush.2, bind.2, brk.2, cacheflush.2, capget.2, chdir.2, chmod.2, chown.2, chroot.2, clock_getres.2, clock_nanosleep.2, clone.2, close.2, connect.2, create_module.2, delete_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, exit_group.2, faccessat.2, fchmodat.2, fchownat.2, fcntl.2, flock.2, fork.2, fstatat.2, fsync.2, futex.2, futimesat.2, get_kernel_syms.2, get_robust_list.2, get_thread_area.2, getcpu.2, getdents.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpid.2, getpriority.2, getresuid.2, getrlimit.2, getrusage.2, getsid.2, getsockname.2, getsockopt.2, gettid.2, gettimeofday.2, getuid.2, getunwind.2, getxattr.2, idle.2, init_module.2, inotify_add_watch.2, inotify_init.2, inotify_rm_watch.2, intro.2, io_cancel.2, io_destroy.2, io_getevents.2, io_setup.2, io_submit.2, ioctl.2, ioctl_list.2, ioperm.2, iopl.2, ioprio_set.2, ipc.2, kcmp.2, kill.2, killpg.2, link.2, linkat.2, listen.2, listxattr.2, llseek.2, lookup_dcookie.2, lseek.2, madvise.2, migrate_pages.2, mincore.2, mkdir.2, mkdirat.2, mknod.2, mknodat.2, mlock.2, mmap.2, mmap2.2, modify_ldt.2, mount.2, move_pages.2, mprotect.2, mq_getsetattr.2, mremap.2, msgctl.2, msgget.2, msgop.2, msync.2, nanosleep.2, nfsservctl.2, nice.2, open.2, openat.2, outb.2, pause.2, pciconfig_read.2, perf_event_open.2, perfmonctl.2, personality.2, pipe.2, pivot_root.2, poll.2, posix_fadvise.2, prctl.2, pread.2, process_vm_readv.2, ptrace.2, query_module.2, quotactl.2, read.2, readahead.2, readdir.2, readlink.2, readlinkat.2, readv.2, reboot.2, recv.2, remap_file_pages.2, removexattr.2, rename.2, renameat.2, rmdir.2, rt_sigqueueinfo.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, select.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, set_thread_area.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, setup.2, setxattr.2, shmctl.2, shmget.2, shmop.2, shutdown.2, sigaction.2, sigaltstack.2, signal.2, signalfd.2, sigpending.2, sigprocmask.2, sigreturn.2, sigsuspend.2, sigwaitinfo.2, socket.2, socketcall.2, socketpair.2, splice.2, stat.2, statfs.2, stime.2, swapon.2, symlink.2, symlinkat.2, sync.2, sync_file_range.2, sysctl.2, sysfs.2, sysinfo.2, syslog.2, tee.2, time.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, uname.2, unimplemented.2, unlink.2, unlinkat.2, uselib.2, ustat.2, utime.2, utimensat.2, vfork.2, vhangup.2, vm86.2, vmsplice.2, wait.2, wait4.2, write.2, CPU_SET.3, INFINITY.3, MB_CUR_MAX.3, MB_LEN_MAX.3, __setfpucw.3, a64l.3, abort.3, abs.3, acos.3, acosh.3, addseverity.3, adjtime.3, aio_cancel.3, aio_error.3, aio_fsync.3, aio_read.3, aio_return.3, aio_suspend.3, aio_write.3, alloca.3, argz_add.3, asin.3, asinh.3, asprintf.3, assert.3, assert_perror.3, atan.3, atan2.3, atanh.3, atexit.3, atof.3, atoi.3, backtrace.3, basename.3, bcmp.3, bcopy.3, bindresvport.3, bsd_signal.3, bsearch.3, bstring.3, btowc.3, btree.3, byteorder.3, bzero.3, cabs.3, cacos.3, cacosh.3, canonicalize_file_name.3, carg.3, casin.3, casinh.3, catan.3, catanh.3, catgets.3, catopen.3, cbrt.3, ccos.3, ccosh.3, ceil.3, cerf.3, cexp.3, cexp2.3, cfree.3, cimag.3, clearenv.3, clock.3, clock_getcpuclockid.3, clog.3, clog10.3, clog2.3, closedir.3, cmsg.3, confstr.3, conj.3, copysign.3, cos.3, cosh.3, cpow.3, cproj.3, creal.3, crypt.3, csin.3, csinh.3, csqrt.3, ctan.3, ctanh.3, ctermid.3, ctime.3, daemon.3, dbopen.3, des_crypt.3, difftime.3, dirfd.3, div.3, dl_iterate_phdr.3, dlopen.3, dprintf.3, drand48.3, drand48_r.3, dysize.3, ecvt.3, ecvt_r.3, encrypt.3, end.3, endian.3, envz_add.3, erf.3, erfc.3, err.3, errno.3, error.3, ether_aton.3, euidaccess.3, exec.3, exit.3, exp.3, exp10.3, exp2.3, expm1.3, fabs.3, fclose.3, fcloseall.3, fdim.3, fenv.3, ferror.3, fexecve.3, fflush.3, ffs.3, fgetgrent.3, fgetpwent.3, fgetwc.3, fgetws.3, finite.3, flockfile.3, floor.3, fma.3, fmax.3, fmemopen.3, fmin.3, fmod.3, fmtmsg.3, fnmatch.3, fopen.3, fpathconf.3, fpclassify.3, fpurge.3, fputwc.3, fputws.3, fread.3, frexp.3, fseek.3, fseeko.3, ftime.3, ftok.3, fts.3, ftw.3, futimes.3, fwide.3, gamma.3, gcvt.3, getaddrinfo.3, getaddrinfo_a.3, getauxval.3, getcontext.3, getcwd.3, getdate.3, getdirentries.3, getdtablesize.3, getenv.3, getfsent.3, getgrent.3, getgrent_r.3, getgrnam.3, getgrouplist.3, gethostbyname.3, gethostid.3, getipnodebyname.3, getline.3, getloadavg.3, getlogin.3, getmntent.3, getnameinfo.3, getnetent.3, getnetent_r.3, getopt.3, getpass.3, getprotoent.3, getprotoent_r.3, getpt.3, getpw.3, getpwent.3, getpwent_r.3, getpwnam.3, getrpcent.3, getrpcent_r.3, getrpcport.3, gets.3, getservent.3, getservent_r.3, getspnam.3, getttyent.3, getumask.3, getusershell.3, getutent.3, getw.3, getwchar.3, glob.3, grantpt.3, gsignal.3, hash.3, hsearch.3, hypot.3, iconv.3, iconv_close.3, iconv_open.3, ilogb.3, index.3, inet.3, inet_ntop.3, inet_pton.3, infnan.3, initgroups.3, insque.3, intro.3, isalpha.3, isatty.3, isgreater.3, iswalnum.3, iswalpha.3, iswblank.3, iswcntrl.3, iswctype.3, iswdigit.3, iswgraph.3, iswlower.3, iswprint.3, iswpunct.3, iswspace.3, iswupper.3, iswxdigit.3, j0.3, key_setsecret.3, ldexp.3, lgamma.3, lio_listio.3, localeconv.3, lockf.3, log.3, log10.3, log1p.3, log2.3, logb.3, login.3, longjmp.3, lrint.3, lround.3, lsearch.3, lseek64.3, makecontext.3, makedev.3, malloc.3, malloc_hook.3, mblen.3, mbrlen.3, mbrtowc.3, mbsinit.3, mbsnrtowcs.3, mbsrtowcs.3, mbstowcs.3, mbtowc.3, memccpy.3, memchr.3, memcmp.3, memcpy.3, memfrob.3, memmem.3, memmove.3, mempcpy.3, memset.3, mkdtemp.3, mkfifo.3, mkfifoat.3, mkstemp.3, mktemp.3, modf.3, mpool.3, mq_close.3, mq_getattr.3, mq_notify.3, mq_open.3, mq_receive.3, mq_send.3, mq_unlink.3, mtrace.3, nan.3, netlink.3, nextafter.3, nl_langinfo.3, offsetof.3, on_exit.3, opendir.3, openpty.3, perror.3, popen.3, posix_fallocate.3, posix_memalign.3, posix_openpt.3, pow.3, pow10.3, printf.3, profil.3, program_invocation_name.3, psignal.3, pthread_kill_other_threads_np.3, ptsname.3, putenv.3, putgrent.3, putpwent.3, puts.3, putwchar.3, qecvt.3, qsort.3, queue.3, raise.3, rand.3, random.3, random_r.3, rcmd.3, re_comp.3, readdir.3, realpath.3, recno.3, regex.3, remainder.3, remove.3, remquo.3, resolver.3, rewinddir.3, rexec.3, rint.3, round.3, rpc.3, rpmatch.3, rtime.3, rtnetlink.3, scalb.3, scalbln.3, scandir.3, scandirat.3, scanf.3, seekdir.3, sem_close.3, sem_destroy.3, sem_getvalue.3, sem_init.3, sem_open.3, sem_post.3, sem_unlink.3, sem_wait.3, setaliasent.3, setbuf.3, setenv.3, setjmp.3, setlocale.3, setlogmask.3, setnetgrent.3, shm_open.3, siginterrupt.3, signbit.3, significand.3, sigpause.3, sigqueue.3, sigset.3, sigsetops.3, sigvec.3, sin.3, sincos.3, sinh.3, sleep.3, sockatmark.3, sqrt.3, statvfs.3, stdarg.3, stdin.3, stdio.3, stdio_ext.3, stpcpy.3, stpncpy.3, strcasecmp.3, strcat.3, strchr.3, strcmp.3, strcoll.3, strcpy.3, strdup.3, strerror.3, strfmon.3, strfry.3, strftime.3, string.3, strlen.3, strnlen.3, strpbrk.3, strptime.3, strsep.3, strsignal.3, strspn.3, strstr.3, strtod.3, strtoimax.3, strtok.3, strtol.3, strtoul.3, strverscmp.3, strxfrm.3, swab.3, sysconf.3, syslog.3, system.3, sysv_signal.3, tan.3, tanh.3, tcgetpgrp.3, tcgetsid.3, telldir.3, tempnam.3, termios.3, tgamma.3, timegm.3, timeradd.3, tmpfile.3, tmpnam.3, toascii.3, toupper.3, towctrans.3, towlower.3, towupper.3, trunc.3, tsearch.3, ttyname.3, ttyslot.3, tzset.3, ualarm.3, ulimit.3, ungetwc.3, unlocked_stdio.3, unlockpt.3, updwtmp.3, usleep.3, wcpcpy.3, wcpncpy.3, wcrtomb.3, wcscasecmp.3, wcscat.3, wcschr.3, wcscmp.3, wcscpy.3, wcscspn.3, wcsdup.3, wcslen.3, wcsncasecmp.3, wcsncat.3, wcsncmp.3, wcsncpy.3, wcsnlen.3, wcsnrtombs.3, wcspbrk.3, wcsrchr.3, wcsrtombs.3, wcsspn.3, wcsstr.3, wcstoimax.3, wcstok.3, wcstombs.3, wcswidth.3, wctob.3, wctomb.3, wctrans.3, wctype.3, wcwidth.3, wmemchr.3, wmemcmp.3, wmemcpy.3, wmemmove.3, wmemset.3, wordexp.3, wprintf.3, xcrypt.3, xdr.3, y0.3, cciss.4, console.4, console_codes.4, console_ioctl.4, dsp56k.4, fd.4, full.4, hd.4, hpsa.4, initrd.4, intro.4, lp.4, mem.4, mouse.4, null.4, pts.4, ram.4, random.4, rtc.4, sk98lin.4, st.4, tty.4, ttyS.4, tty_ioctl.4, vcs.4, wavelan.4, acct.5, charmap.5, dir_colors.5, filesystems.5, ftpusers.5, group.5, host.conf.5, hosts.5, hosts.equiv.5, intro.5, issue.5, locale.5, motd.5, networks.5, nologin.5, nscd.conf.5, passwd.5, proc.5, protocols.5, resolv.conf.5, rpc.5, securetty.5, services.5, shells.5, termcap.5, ttytype.5, utmp.5, armscii-8.7, arp.7, ascii.7, bootparam.7, capabilities.7, charsets.7, complex.7, cp1251.7, credentials.7, ddp.7, environ.7, epoll.7, fifo.7, futex.7, glob.7, hier.7, icmp.7, inotify.7, intro.7, ip.7, ipv6.7, iso_8859-1.7, iso_8859-10.7, iso_8859-11.7, iso_8859-13.7, iso_8859-14.7, iso_8859-15.7, iso_8859-16.7, iso_8859-2.7, iso_8859-3.7, iso_8859-4.7, iso_8859-5.7, iso_8859-6.7, iso_8859-7.7, iso_8859-8.7, iso_8859-9.7, koi8-r.7, koi8-u.7, locale.7, mailaddr.7, man.7, mq_overview.7, netdevice.7, netlink.7, numa.7, packet.7, path_resolution.7, pipe.7, posixoptions.7, pthreads.7, pty.7, raw.7, regex.7, rtld-audit.7, rtnetlink.7, sem_overview.7, shm_overview.7, sigevent.7, signal.7, socket.7, standards.7, suffixes.7, svipc.7, tcp.7, termio.7, time.7, udp.7, udplite.7, unicode.7, unix.7, uri.7, utf-8.7, x25.7, nscd.8, sync.8, tzselect.8, zdump.8, zic.8: Global fix: remove unneeded double quotes in .SH headings
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2013-02-24 18:01:36 +00:00
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.SH CONFORMING TO
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2007-05-18 16:06:42 +00:00
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POSIX.1-2001, SVr4, 4.4BSD (this call first appeared in 4.2BSD).
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2008-08-06 10:30:51 +00:00
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POSIX.1-2008 marks
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.BR getitimer ()
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and
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.BR setitimer ()
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2009-03-14 17:48:16 +00:00
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obsolete, recommending the use of the POSIX timers API
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.RB ( timer_gettime (2),
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.BR timer_settime (2),
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etc.) instead.
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2006-07-22 15:54:34 +00:00
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.SH NOTES
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2016-07-05 08:53:49 +00:00
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Timers will never expire before the requested time,
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but may expire some (short) time afterward, which depends
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on the system timer resolution and on the system load; see
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.BR time (7).
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(But see BUGS below.)
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If the timer expires while the process is active (always true for
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.BR ITIMER_VIRTUAL ),
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the signal will be delivered immediately when generated.
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2006-07-22 15:54:34 +00:00
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A child created via
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.BR fork (2)
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does not inherit its parent's interval timers.
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2007-04-12 22:42:49 +00:00
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Interval timers are preserved across an
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2006-07-22 15:54:34 +00:00
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.BR execve (2).
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2008-06-23 10:28:23 +00:00
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2008-06-25 15:32:01 +00:00
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POSIX.1 leaves the
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2008-06-23 10:28:23 +00:00
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interaction between
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2010-11-01 06:38:59 +00:00
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.BR setitimer ()
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2008-06-27 12:10:15 +00:00
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and the three interfaces
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2008-06-23 10:28:23 +00:00
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.BR alarm (2),
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.BR sleep (3),
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and
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.BR usleep (3)
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unspecified.
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2012-10-01 08:20:08 +00:00
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The standards are silent on the meaning of the call:
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setitimer(which, NULL, &old_value);
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Many systems (Solaris, the BSDs, and perhaps others)
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treat this as equivalent to:
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getitimer(which, &old_value);
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In Linux, this is treated as being equivalent to a call in which the
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.I new_value
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fields are zero; that is, the timer is disabled.
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.IR "Don't use this Linux misfeature" :
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it is nonportable and unnecessary.
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2004-11-03 13:51:07 +00:00
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.SH BUGS
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Salut Olivier (and Nishanth),
Regarding man page documentation of the problem of short sleeps
for setiteimer(2)...
> > -- pointers to those threads
>
> http://bugzilla.kernel.org/show_bug.cgi?id=4569
> http://lkml.org/lkml/2005/4/29/163
>
> > -- indications of which kernel versions show this bahaviour
>
> AFAIK, all versions as far as x86 is concerned.
> Dunno if it is hardware specific.
>
> > -- a (short) test program to demonstrate it, if you have one.
>
> See the bugzilla bug's attachments
Sorry for the long delay in following this up, but I've got to
it now. I tweaked your suggestions slightly:
{{
Timers will never expire before the requested time,
-instead expiring some short, constant time afterwards, dependent
-on the system timer resolution (currently 10ms).
+but may expire some (short) time afterwards, which depends
+on the system timer resolution and on the system load.
+Upon expiration, a signal will be generated and the timer reset.
+If the timer expires while the process is active (always true for
+On certain systems (including x86), the Linux kernel has a bug which will
+produce premature timer expirations of up to one jiffy under some
+circumstances.
}}
Thanks for this bug reporet,
Nishanth: if and when your changes are accepted, and the problem
is thus fixed, could you please send me a notification of that
fact, and I can then further amend the manual pages.
Cheers,
Michael
/* itimer_short_interval_bug.c
June 2005
In current Linux kernels, an interval timer set using setitimer()
can sometimes sleep *less* than the specified interval.
This program demonstrates the behaviour by looping through all
itimer values from 1 microsecond upwards, in one microsecond steps.
*/
/* Adapted from a program by Olivier Croquette, June 2005 */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/wait.h>
typedef unsigned long long int u_time_t; /* in microsecs */
static int handler_flag;
/* return time as a number of microsecs */
static u_time_t
gettime(void )
{
struct timeval tv;
if ( gettimeofday(&tv, NULL) == -1) {
perror("gettimeofday()");
return 0;
}
return (tv.tv_usec + tv.tv_sec * 1000000LL);
}
static void
handler (int sig, siginfo_t *siginfo, void *context)
{
handler_flag++;
return ;
}
/* Sleep for 'time' microsecs. */
static int
isleep(u_time_t time)
{
struct itimerval newtv;
sigset_t sigset;
struct sigaction sigact;
if (time == 0)
return 0;
/* block SIGALRM */
sigemptyset (&sigset);
sigaddset (&sigset, SIGALRM);
sigprocmask (SIG_BLOCK, &sigset, NULL);
/* set up our handler */
sigact.sa_sigaction = handler;
sigemptyset(&sigact.sa_mask);
sigact.sa_flags = SA_SIGINFO;
sigaction (SIGALRM, &sigact, NULL);
newtv.it_interval.tv_sec = 0;
newtv.it_interval.tv_usec = 0;
newtv.it_value.tv_sec = time / 1000000;
newtv.it_value.tv_usec = time % 1000000;
if (setitimer(ITIMER_REAL,&newtv,NULL) == -1) {
perror("setitimer(set)");
return 1;
}
sigemptyset (&sigset);
sigsuspend (&sigset);
return 0;
}
int
main(int argc, char *argv[]) {
u_time_t wait;
int loop, numLoops;
u_time_t t1, t2;
u_time_t actual;
long long minDiff, maxDiff, totDiff, diff;
int numFail = 0;
if (argc != 2) {
fprintf(stderr, "Usage: %s num-loops\n", argv[0]);
exit(EXIT_FAILURE);
} /* if */
numLoops = atoi(argv[1]);
setbuf(stdout, NULL);
for (wait = 1; ; wait++) {
maxDiff = 0;
numFail = 0;
totDiff = 0;
minDiff = -wait;
if (wait % 10000 == 0)
printf("%llu\n", wait);
for (loop = 0; loop < numLoops; loop++) {
t1 = gettime();
handler_flag = 0;
isleep(wait);
if ( handler_flag != 1 )
printf("Problem with the handler flag (%d)!\n", handler_flag);
t2 = gettime();
actual = t2 - t1;
if ( actual < wait ) {
diff = actual - wait;
if (diff < maxDiff)
maxDiff = diff;
if (diff > minDiff)
minDiff = diff;
totDiff += diff;
numFail++;
} /* if */
} /* for */
if (numFail > 0)
printf("%llu: %3d fail (%4lld %4lld; avg=%6.1f)\n",
wait, numFail, minDiff, maxDiff,
(double) totDiff / numFail);
} /* for */
return 0;
} /* main */
2005-06-13 09:01:49 +00:00
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The generation and delivery of a signal are distinct, and
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only one instance of each of the signals listed above may be pending
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for a process.
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2007-12-19 06:29:23 +00:00
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Under very heavy loading, an
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2004-11-03 13:51:07 +00:00
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.B ITIMER_REAL
|
Salut Olivier (and Nishanth),
Regarding man page documentation of the problem of short sleeps
for setiteimer(2)...
> > -- pointers to those threads
>
> http://bugzilla.kernel.org/show_bug.cgi?id=4569
> http://lkml.org/lkml/2005/4/29/163
>
> > -- indications of which kernel versions show this bahaviour
>
> AFAIK, all versions as far as x86 is concerned.
> Dunno if it is hardware specific.
>
> > -- a (short) test program to demonstrate it, if you have one.
>
> See the bugzilla bug's attachments
Sorry for the long delay in following this up, but I've got to
it now. I tweaked your suggestions slightly:
{{
Timers will never expire before the requested time,
-instead expiring some short, constant time afterwards, dependent
-on the system timer resolution (currently 10ms).
+but may expire some (short) time afterwards, which depends
+on the system timer resolution and on the system load.
+Upon expiration, a signal will be generated and the timer reset.
+If the timer expires while the process is active (always true for
+On certain systems (including x86), the Linux kernel has a bug which will
+produce premature timer expirations of up to one jiffy under some
+circumstances.
}}
Thanks for this bug reporet,
Nishanth: if and when your changes are accepted, and the problem
is thus fixed, could you please send me a notification of that
fact, and I can then further amend the manual pages.
Cheers,
Michael
/* itimer_short_interval_bug.c
June 2005
In current Linux kernels, an interval timer set using setitimer()
can sometimes sleep *less* than the specified interval.
This program demonstrates the behaviour by looping through all
itimer values from 1 microsecond upwards, in one microsecond steps.
*/
/* Adapted from a program by Olivier Croquette, June 2005 */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/wait.h>
typedef unsigned long long int u_time_t; /* in microsecs */
static int handler_flag;
/* return time as a number of microsecs */
static u_time_t
gettime(void )
{
struct timeval tv;
if ( gettimeofday(&tv, NULL) == -1) {
perror("gettimeofday()");
return 0;
}
return (tv.tv_usec + tv.tv_sec * 1000000LL);
}
static void
handler (int sig, siginfo_t *siginfo, void *context)
{
handler_flag++;
return ;
}
/* Sleep for 'time' microsecs. */
static int
isleep(u_time_t time)
{
struct itimerval newtv;
sigset_t sigset;
struct sigaction sigact;
if (time == 0)
return 0;
/* block SIGALRM */
sigemptyset (&sigset);
sigaddset (&sigset, SIGALRM);
sigprocmask (SIG_BLOCK, &sigset, NULL);
/* set up our handler */
sigact.sa_sigaction = handler;
sigemptyset(&sigact.sa_mask);
sigact.sa_flags = SA_SIGINFO;
sigaction (SIGALRM, &sigact, NULL);
newtv.it_interval.tv_sec = 0;
newtv.it_interval.tv_usec = 0;
newtv.it_value.tv_sec = time / 1000000;
newtv.it_value.tv_usec = time % 1000000;
if (setitimer(ITIMER_REAL,&newtv,NULL) == -1) {
perror("setitimer(set)");
return 1;
}
sigemptyset (&sigset);
sigsuspend (&sigset);
return 0;
}
int
main(int argc, char *argv[]) {
u_time_t wait;
int loop, numLoops;
u_time_t t1, t2;
u_time_t actual;
long long minDiff, maxDiff, totDiff, diff;
int numFail = 0;
if (argc != 2) {
fprintf(stderr, "Usage: %s num-loops\n", argv[0]);
exit(EXIT_FAILURE);
} /* if */
numLoops = atoi(argv[1]);
setbuf(stdout, NULL);
for (wait = 1; ; wait++) {
maxDiff = 0;
numFail = 0;
totDiff = 0;
minDiff = -wait;
if (wait % 10000 == 0)
printf("%llu\n", wait);
for (loop = 0; loop < numLoops; loop++) {
t1 = gettime();
handler_flag = 0;
isleep(wait);
if ( handler_flag != 1 )
printf("Problem with the handler flag (%d)!\n", handler_flag);
t2 = gettime();
actual = t2 - t1;
if ( actual < wait ) {
diff = actual - wait;
if (diff < maxDiff)
maxDiff = diff;
if (diff > minDiff)
minDiff = diff;
totDiff += diff;
numFail++;
} /* if */
} /* for */
if (numFail > 0)
printf("%llu: %3d fail (%4lld %4lld; avg=%6.1f)\n",
wait, numFail, minDiff, maxDiff,
(double) totDiff / numFail);
} /* for */
return 0;
} /* main */
2005-06-13 09:01:49 +00:00
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timer may expire before the signal from a previous expiration
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has been delivered.
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2004-11-03 13:51:07 +00:00
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The second signal in such an event will be lost.
|
2005-04-06 15:29:32 +00:00
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2008-06-23 10:28:23 +00:00
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On Linux kernels before 2.6.16, timer values are represented in jiffies.
|
2007-04-12 22:42:49 +00:00
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If a request is made set a timer with a value whose jiffies
|
2007-06-22 17:16:20 +00:00
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representation exceeds
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.B MAX_SEC_IN_JIFFIES
|
2005-04-06 15:29:32 +00:00
|
|
|
(defined in
|
|
|
|
.IR include/linux/jiffies.h ),
|
|
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then the timer is silently truncated to this ceiling value.
|
2008-05-07 13:33:52 +00:00
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|
On Linux/i386 (where, since Linux 2.6.13,
|
2006-04-26 04:42:14 +00:00
|
|
|
the default jiffy is 0.004 seconds),
|
2005-04-06 15:29:32 +00:00
|
|
|
this means that the ceiling value for a timer is
|
2006-04-26 04:42:14 +00:00
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|
|
approximately 99.42 days.
|
2008-06-23 10:28:23 +00:00
|
|
|
Since Linux 2.6.16,
|
|
|
|
the kernel uses a different internal representation for times,
|
|
|
|
and this ceiling is removed.
|
2005-04-06 15:29:32 +00:00
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2007-12-24 17:31:35 +00:00
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On certain systems (including i386),
|
2007-04-12 22:42:49 +00:00
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Linux kernels before version 2.6.12 have a bug which will produce
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2005-06-23 07:16:55 +00:00
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premature timer expirations of up to one jiffy under some circumstances.
|
|
|
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This bug is fixed in kernel 2.6.12.
|
Von: "Michael Kerrisk" <mtk-manpages@gmx.net>
An: Olivier Croquette <ocroquette@free.fr>
Betreff: Re: 2.6.12 and setitimer
Datum: Mon, 4 Jul 2005 08:36:35 +0200 (MEST)
Hi Olivier,
> You will probably consider adding also a note to point out that the bug
> will stay a known bug of the 2.4 serie:
>
> http://lkml.org/lkml/2005/7/1/165
First off, I _very_ much appreciate the fact that you keep
informing me of the progress of this bug! Thank you.
At the moment, I'm inlined yo leave the manual page as it is.
It currently reads:
On certain systems (including x86), Linux ker‐
nels before version 2.6.12 have a bug which
will produce premature timer expirations of up
to one jiffy under some circumstances. This
bug is fixed in kernel 2.6.12.
To me that implies that the bug also affects kernels before
2.4 -- e.g., 2.4.x. Now, what would be interesting is if the
bug *does* get fixed in 2.4, then I could also add a note
about the 2.4.x version where it is fixed.
In the meantime, I have added a note to myself (i.e., a comment
in the man page source) about this point.
If the bug *does* eventually get fixed in 2.4.x, and you
hear of it, please do let me know.
Thanks,
Michael
2005-07-04 06:44:50 +00:00
|
|
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.\" 4 Jul 2005: It looks like this bug may remain in 2.4.x.
|
|
|
|
.\" http://lkml.org/lkml/2005/7/1/165
|
Salut Olivier (and Nishanth),
Regarding man page documentation of the problem of short sleeps
for setiteimer(2)...
> > -- pointers to those threads
>
> http://bugzilla.kernel.org/show_bug.cgi?id=4569
> http://lkml.org/lkml/2005/4/29/163
>
> > -- indications of which kernel versions show this bahaviour
>
> AFAIK, all versions as far as x86 is concerned.
> Dunno if it is hardware specific.
>
> > -- a (short) test program to demonstrate it, if you have one.
>
> See the bugzilla bug's attachments
Sorry for the long delay in following this up, but I've got to
it now. I tweaked your suggestions slightly:
{{
Timers will never expire before the requested time,
-instead expiring some short, constant time afterwards, dependent
-on the system timer resolution (currently 10ms).
+but may expire some (short) time afterwards, which depends
+on the system timer resolution and on the system load.
+Upon expiration, a signal will be generated and the timer reset.
+If the timer expires while the process is active (always true for
+On certain systems (including x86), the Linux kernel has a bug which will
+produce premature timer expirations of up to one jiffy under some
+circumstances.
}}
Thanks for this bug reporet,
Nishanth: if and when your changes are accepted, and the problem
is thus fixed, could you please send me a notification of that
fact, and I can then further amend the manual pages.
Cheers,
Michael
/* itimer_short_interval_bug.c
June 2005
In current Linux kernels, an interval timer set using setitimer()
can sometimes sleep *less* than the specified interval.
This program demonstrates the behaviour by looping through all
itimer values from 1 microsecond upwards, in one microsecond steps.
*/
/* Adapted from a program by Olivier Croquette, June 2005 */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/wait.h>
typedef unsigned long long int u_time_t; /* in microsecs */
static int handler_flag;
/* return time as a number of microsecs */
static u_time_t
gettime(void )
{
struct timeval tv;
if ( gettimeofday(&tv, NULL) == -1) {
perror("gettimeofday()");
return 0;
}
return (tv.tv_usec + tv.tv_sec * 1000000LL);
}
static void
handler (int sig, siginfo_t *siginfo, void *context)
{
handler_flag++;
return ;
}
/* Sleep for 'time' microsecs. */
static int
isleep(u_time_t time)
{
struct itimerval newtv;
sigset_t sigset;
struct sigaction sigact;
if (time == 0)
return 0;
/* block SIGALRM */
sigemptyset (&sigset);
sigaddset (&sigset, SIGALRM);
sigprocmask (SIG_BLOCK, &sigset, NULL);
/* set up our handler */
sigact.sa_sigaction = handler;
sigemptyset(&sigact.sa_mask);
sigact.sa_flags = SA_SIGINFO;
sigaction (SIGALRM, &sigact, NULL);
newtv.it_interval.tv_sec = 0;
newtv.it_interval.tv_usec = 0;
newtv.it_value.tv_sec = time / 1000000;
newtv.it_value.tv_usec = time % 1000000;
if (setitimer(ITIMER_REAL,&newtv,NULL) == -1) {
perror("setitimer(set)");
return 1;
}
sigemptyset (&sigset);
sigsuspend (&sigset);
return 0;
}
int
main(int argc, char *argv[]) {
u_time_t wait;
int loop, numLoops;
u_time_t t1, t2;
u_time_t actual;
long long minDiff, maxDiff, totDiff, diff;
int numFail = 0;
if (argc != 2) {
fprintf(stderr, "Usage: %s num-loops\n", argv[0]);
exit(EXIT_FAILURE);
} /* if */
numLoops = atoi(argv[1]);
setbuf(stdout, NULL);
for (wait = 1; ; wait++) {
maxDiff = 0;
numFail = 0;
totDiff = 0;
minDiff = -wait;
if (wait % 10000 == 0)
printf("%llu\n", wait);
for (loop = 0; loop < numLoops; loop++) {
t1 = gettime();
handler_flag = 0;
isleep(wait);
if ( handler_flag != 1 )
printf("Problem with the handler flag (%d)!\n", handler_flag);
t2 = gettime();
actual = t2 - t1;
if ( actual < wait ) {
diff = actual - wait;
if (diff < maxDiff)
maxDiff = diff;
if (diff > minDiff)
minDiff = diff;
totDiff += diff;
numFail++;
} /* if */
} /* for */
if (numFail > 0)
printf("%llu: %3d fail (%4lld %4lld; avg=%6.1f)\n",
wait, numFail, minDiff, maxDiff,
(double) totDiff / numFail);
} /* for */
return 0;
} /* main */
2005-06-13 09:01:49 +00:00
|
|
|
|
2006-08-04 12:39:17 +00:00
|
|
|
POSIX.1-2001 says that
|
2005-06-23 07:16:55 +00:00
|
|
|
.BR setitimer ()
|
2005-04-06 15:29:32 +00:00
|
|
|
should fail if a
|
|
|
|
.I tv_usec
|
|
|
|
value is specified that is outside of the range 0 to 999999.
|
2007-08-28 13:15:35 +00:00
|
|
|
However, in kernels up to and including 2.6.21,
|
|
|
|
Linux does not give an error, but instead silently
|
2005-04-06 15:29:32 +00:00
|
|
|
adjusts the corresponding seconds value for the timer.
|
Changes.old, clone.2, execve.2, fcntl.2, futex.2, getitimer.2, getpriority.2, mmap.2, mount.2, mprotect.2, sched_setscheduler.2, select_tut.2, setuid.2, sigaltstack.2, vfork.2, div.3, fenv.3, fmod.3, memchr.3, pthread_attr_setstackaddr.3, pthread_attr_setstacksize.3, pthread_getattr_np.3, queue.3, scanf.3, trunc.3, st.4, proc.5, services.5, utmp.5, bootparam.7, capabilities.7, feature_test_macros.7, futex.7, glob.7, man.7, netlink.7, unicode.7: Switch to American usage: "-wards" ==> "-ward"
American English uses "afterward" in preference to "afterwards",
and so on
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-09-26 05:34:47 +00:00
|
|
|
From kernel 2.6.22 onward,
|
2010-01-16 16:48:00 +00:00
|
|
|
this nonconformance has been repaired:
|
2007-08-28 13:15:35 +00:00
|
|
|
an improper
|
2006-04-26 19:39:33 +00:00
|
|
|
.I tv_usec
|
2007-08-28 13:15:35 +00:00
|
|
|
value results in an
|
|
|
|
.B EINVAL
|
|
|
|
error.
|
|
|
|
.\" Bugzilla report 25 Apr 2006:
|
2006-04-26 04:42:14 +00:00
|
|
|
.\" http://bugzilla.kernel.org/show_bug.cgi?id=6443
|
2010-01-16 16:54:51 +00:00
|
|
|
.\" "setitimer() should reject noncanonical arguments"
|
getent.1, intro.1, time.1, _exit.2, _syscall.2, accept.2, access.2, acct.2, adjtimex.2, alarm.2, alloc_hugepages.2, arch_prctl.2, bdflush.2, bind.2, brk.2, cacheflush.2, capget.2, chdir.2, chmod.2, chown.2, chroot.2, clock_getres.2, clock_nanosleep.2, clone.2, close.2, connect.2, create_module.2, delete_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, exit_group.2, faccessat.2, fchmodat.2, fchownat.2, fcntl.2, flock.2, fork.2, fstatat.2, fsync.2, futex.2, futimesat.2, get_kernel_syms.2, get_robust_list.2, get_thread_area.2, getcpu.2, getdents.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpid.2, getpriority.2, getresuid.2, getrlimit.2, getrusage.2, getsid.2, getsockname.2, getsockopt.2, gettid.2, gettimeofday.2, getuid.2, getunwind.2, getxattr.2, idle.2, init_module.2, inotify_add_watch.2, inotify_init.2, inotify_rm_watch.2, intro.2, io_cancel.2, io_destroy.2, io_getevents.2, io_setup.2, io_submit.2, ioctl.2, ioctl_list.2, ioperm.2, iopl.2, ioprio_set.2, ipc.2, kcmp.2, kill.2, killpg.2, link.2, linkat.2, listen.2, listxattr.2, llseek.2, lookup_dcookie.2, lseek.2, madvise.2, migrate_pages.2, mincore.2, mkdir.2, mkdirat.2, mknod.2, mknodat.2, mlock.2, mmap.2, mmap2.2, modify_ldt.2, mount.2, move_pages.2, mprotect.2, mq_getsetattr.2, mremap.2, msgctl.2, msgget.2, msgop.2, msync.2, nanosleep.2, nfsservctl.2, nice.2, open.2, openat.2, outb.2, pause.2, pciconfig_read.2, perf_event_open.2, perfmonctl.2, personality.2, pipe.2, pivot_root.2, poll.2, posix_fadvise.2, prctl.2, pread.2, process_vm_readv.2, ptrace.2, query_module.2, quotactl.2, read.2, readahead.2, readdir.2, readlink.2, readlinkat.2, readv.2, reboot.2, recv.2, remap_file_pages.2, removexattr.2, rename.2, renameat.2, rmdir.2, rt_sigqueueinfo.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, select.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, set_thread_area.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, setup.2, setxattr.2, shmctl.2, shmget.2, shmop.2, shutdown.2, sigaction.2, sigaltstack.2, signal.2, signalfd.2, sigpending.2, sigprocmask.2, sigreturn.2, sigsuspend.2, sigwaitinfo.2, socket.2, socketcall.2, socketpair.2, splice.2, stat.2, statfs.2, stime.2, swapon.2, symlink.2, symlinkat.2, sync.2, sync_file_range.2, sysctl.2, sysfs.2, sysinfo.2, syslog.2, tee.2, time.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, uname.2, unimplemented.2, unlink.2, unlinkat.2, uselib.2, ustat.2, utime.2, utimensat.2, vfork.2, vhangup.2, vm86.2, vmsplice.2, wait.2, wait4.2, write.2, CPU_SET.3, INFINITY.3, MB_CUR_MAX.3, MB_LEN_MAX.3, __setfpucw.3, a64l.3, abort.3, abs.3, acos.3, acosh.3, addseverity.3, adjtime.3, aio_cancel.3, aio_error.3, aio_fsync.3, aio_read.3, aio_return.3, aio_suspend.3, aio_write.3, alloca.3, argz_add.3, asin.3, asinh.3, asprintf.3, assert.3, assert_perror.3, atan.3, atan2.3, atanh.3, atexit.3, atof.3, atoi.3, backtrace.3, basename.3, bcmp.3, bcopy.3, bindresvport.3, bsd_signal.3, bsearch.3, bstring.3, btowc.3, btree.3, byteorder.3, bzero.3, cabs.3, cacos.3, cacosh.3, canonicalize_file_name.3, carg.3, casin.3, casinh.3, catan.3, catanh.3, catgets.3, catopen.3, cbrt.3, ccos.3, ccosh.3, ceil.3, cerf.3, cexp.3, cexp2.3, cfree.3, cimag.3, clearenv.3, clock.3, clock_getcpuclockid.3, clog.3, clog10.3, clog2.3, closedir.3, cmsg.3, confstr.3, conj.3, copysign.3, cos.3, cosh.3, cpow.3, cproj.3, creal.3, crypt.3, csin.3, csinh.3, csqrt.3, ctan.3, ctanh.3, ctermid.3, ctime.3, daemon.3, dbopen.3, des_crypt.3, difftime.3, dirfd.3, div.3, dl_iterate_phdr.3, dlopen.3, dprintf.3, drand48.3, drand48_r.3, dysize.3, ecvt.3, ecvt_r.3, encrypt.3, end.3, endian.3, envz_add.3, erf.3, erfc.3, err.3, errno.3, error.3, ether_aton.3, euidaccess.3, exec.3, exit.3, exp.3, exp10.3, exp2.3, expm1.3, fabs.3, fclose.3, fcloseall.3, fdim.3, fenv.3, ferror.3, fexecve.3, fflush.3, ffs.3, fgetgrent.3, fgetpwent.3, fgetwc.3, fgetws.3, finite.3, flockfile.3, floor.3, fma.3, fmax.3, fmemopen.3, fmin.3, fmod.3, fmtmsg.3, fnmatch.3, fopen.3, fpathconf.3, fpclassify.3, fpurge.3, fputwc.3, fputws.3, fread.3, frexp.3, fseek.3, fseeko.3, ftime.3, ftok.3, fts.3, ftw.3, futimes.3, fwide.3, gamma.3, gcvt.3, getaddrinfo.3, getaddrinfo_a.3, getauxval.3, getcontext.3, getcwd.3, getdate.3, getdirentries.3, getdtablesize.3, getenv.3, getfsent.3, getgrent.3, getgrent_r.3, getgrnam.3, getgrouplist.3, gethostbyname.3, gethostid.3, getipnodebyname.3, getline.3, getloadavg.3, getlogin.3, getmntent.3, getnameinfo.3, getnetent.3, getnetent_r.3, getopt.3, getpass.3, getprotoent.3, getprotoent_r.3, getpt.3, getpw.3, getpwent.3, getpwent_r.3, getpwnam.3, getrpcent.3, getrpcent_r.3, getrpcport.3, gets.3, getservent.3, getservent_r.3, getspnam.3, getttyent.3, getumask.3, getusershell.3, getutent.3, getw.3, getwchar.3, glob.3, grantpt.3, gsignal.3, hash.3, hsearch.3, hypot.3, iconv.3, iconv_close.3, iconv_open.3, ilogb.3, index.3, inet.3, inet_ntop.3, inet_pton.3, infnan.3, initgroups.3, insque.3, intro.3, isalpha.3, isatty.3, isgreater.3, iswalnum.3, iswalpha.3, iswblank.3, iswcntrl.3, iswctype.3, iswdigit.3, iswgraph.3, iswlower.3, iswprint.3, iswpunct.3, iswspace.3, iswupper.3, iswxdigit.3, j0.3, key_setsecret.3, ldexp.3, lgamma.3, lio_listio.3, localeconv.3, lockf.3, log.3, log10.3, log1p.3, log2.3, logb.3, login.3, longjmp.3, lrint.3, lround.3, lsearch.3, lseek64.3, makecontext.3, makedev.3, malloc.3, malloc_hook.3, mblen.3, mbrlen.3, mbrtowc.3, mbsinit.3, mbsnrtowcs.3, mbsrtowcs.3, mbstowcs.3, mbtowc.3, memccpy.3, memchr.3, memcmp.3, memcpy.3, memfrob.3, memmem.3, memmove.3, mempcpy.3, memset.3, mkdtemp.3, mkfifo.3, mkfifoat.3, mkstemp.3, mktemp.3, modf.3, mpool.3, mq_close.3, mq_getattr.3, mq_notify.3, mq_open.3, mq_receive.3, mq_send.3, mq_unlink.3, mtrace.3, nan.3, netlink.3, nextafter.3, nl_langinfo.3, offsetof.3, on_exit.3, opendir.3, openpty.3, perror.3, popen.3, posix_fallocate.3, posix_memalign.3, posix_openpt.3, pow.3, pow10.3, printf.3, profil.3, program_invocation_name.3, psignal.3, pthread_kill_other_threads_np.3, ptsname.3, putenv.3, putgrent.3, putpwent.3, puts.3, putwchar.3, qecvt.3, qsort.3, queue.3, raise.3, rand.3, random.3, random_r.3, rcmd.3, re_comp.3, readdir.3, realpath.3, recno.3, regex.3, remainder.3, remove.3, remquo.3, resolver.3, rewinddir.3, rexec.3, rint.3, round.3, rpc.3, rpmatch.3, rtime.3, rtnetlink.3, scalb.3, scalbln.3, scandir.3, scandirat.3, scanf.3, seekdir.3, sem_close.3, sem_destroy.3, sem_getvalue.3, sem_init.3, sem_open.3, sem_post.3, sem_unlink.3, sem_wait.3, setaliasent.3, setbuf.3, setenv.3, setjmp.3, setlocale.3, setlogmask.3, setnetgrent.3, shm_open.3, siginterrupt.3, signbit.3, significand.3, sigpause.3, sigqueue.3, sigset.3, sigsetops.3, sigvec.3, sin.3, sincos.3, sinh.3, sleep.3, sockatmark.3, sqrt.3, statvfs.3, stdarg.3, stdin.3, stdio.3, stdio_ext.3, stpcpy.3, stpncpy.3, strcasecmp.3, strcat.3, strchr.3, strcmp.3, strcoll.3, strcpy.3, strdup.3, strerror.3, strfmon.3, strfry.3, strftime.3, string.3, strlen.3, strnlen.3, strpbrk.3, strptime.3, strsep.3, strsignal.3, strspn.3, strstr.3, strtod.3, strtoimax.3, strtok.3, strtol.3, strtoul.3, strverscmp.3, strxfrm.3, swab.3, sysconf.3, syslog.3, system.3, sysv_signal.3, tan.3, tanh.3, tcgetpgrp.3, tcgetsid.3, telldir.3, tempnam.3, termios.3, tgamma.3, timegm.3, timeradd.3, tmpfile.3, tmpnam.3, toascii.3, toupper.3, towctrans.3, towlower.3, towupper.3, trunc.3, tsearch.3, ttyname.3, ttyslot.3, tzset.3, ualarm.3, ulimit.3, ungetwc.3, unlocked_stdio.3, unlockpt.3, updwtmp.3, usleep.3, wcpcpy.3, wcpncpy.3, wcrtomb.3, wcscasecmp.3, wcscat.3, wcschr.3, wcscmp.3, wcscpy.3, wcscspn.3, wcsdup.3, wcslen.3, wcsncasecmp.3, wcsncat.3, wcsncmp.3, wcsncpy.3, wcsnlen.3, wcsnrtombs.3, wcspbrk.3, wcsrchr.3, wcsrtombs.3, wcsspn.3, wcsstr.3, wcstoimax.3, wcstok.3, wcstombs.3, wcswidth.3, wctob.3, wctomb.3, wctrans.3, wctype.3, wcwidth.3, wmemchr.3, wmemcmp.3, wmemcpy.3, wmemmove.3, wmemset.3, wordexp.3, wprintf.3, xcrypt.3, xdr.3, y0.3, cciss.4, console.4, console_codes.4, console_ioctl.4, dsp56k.4, fd.4, full.4, hd.4, hpsa.4, initrd.4, intro.4, lp.4, mem.4, mouse.4, null.4, pts.4, ram.4, random.4, rtc.4, sk98lin.4, st.4, tty.4, ttyS.4, tty_ioctl.4, vcs.4, wavelan.4, acct.5, charmap.5, dir_colors.5, filesystems.5, ftpusers.5, group.5, host.conf.5, hosts.5, hosts.equiv.5, intro.5, issue.5, locale.5, motd.5, networks.5, nologin.5, nscd.conf.5, passwd.5, proc.5, protocols.5, resolv.conf.5, rpc.5, securetty.5, services.5, shells.5, termcap.5, ttytype.5, utmp.5, armscii-8.7, arp.7, ascii.7, bootparam.7, capabilities.7, charsets.7, complex.7, cp1251.7, credentials.7, ddp.7, environ.7, epoll.7, fifo.7, futex.7, glob.7, hier.7, icmp.7, inotify.7, intro.7, ip.7, ipv6.7, iso_8859-1.7, iso_8859-10.7, iso_8859-11.7, iso_8859-13.7, iso_8859-14.7, iso_8859-15.7, iso_8859-16.7, iso_8859-2.7, iso_8859-3.7, iso_8859-4.7, iso_8859-5.7, iso_8859-6.7, iso_8859-7.7, iso_8859-8.7, iso_8859-9.7, koi8-r.7, koi8-u.7, locale.7, mailaddr.7, man.7, mq_overview.7, netdevice.7, netlink.7, numa.7, packet.7, path_resolution.7, pipe.7, posixoptions.7, pthreads.7, pty.7, raw.7, regex.7, rtld-audit.7, rtnetlink.7, sem_overview.7, shm_overview.7, sigevent.7, signal.7, socket.7, standards.7, suffixes.7, svipc.7, tcp.7, termio.7, time.7, udp.7, udplite.7, unicode.7, unix.7, uri.7, utf-8.7, x25.7, nscd.8, sync.8, tzselect.8, zdump.8, zic.8: Global fix: remove unneeded double quotes in .SH headings
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2013-02-24 18:01:36 +00:00
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.SH SEE ALSO
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2007-05-16 18:25:50 +00:00
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.BR gettimeofday (2),
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.BR sigaction (2),
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.BR signal (2),
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2009-02-10 01:42:17 +00:00
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.BR timer_create (2),
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2008-02-12 14:40:53 +00:00
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.BR timerfd_create (2),
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2007-05-16 18:25:50 +00:00
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.BR time (7)
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