2004-11-03 13:51:07 +00:00
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.\" This manpage is Copyright (C) 1992 Drew Eckhardt;
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2020-02-22 08:52:07 +00:00
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.\" and Copyright (C) 1993 Michael Haardt, Ian Jackson.
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.\" and Copyright (C) 2009-2015 Michael Kerrisk, <mtk.manpages.gmail.com>
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2004-11-03 13:51:07 +00:00
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.\"
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intro.1, _exit.2, access.2, alarm.2, alloc_hugepages.2, arch_prctl.2, bind.2, chdir.2, chmod.2, chown.2, chroot.2, clock_getres.2, clock_nanosleep.2, close.2, connect.2, delete_module.2, dup.2, execve.2, exit_group.2, faccessat.2, fchmodat.2, fchownat.2, fcntl.2, fork.2, fstatat.2, fsync.2, futimesat.2, get_robust_list.2, getdents.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getpagesize.2, getpid.2, getresuid.2, getrlimit.2, getrusage.2, gettid.2, gettimeofday.2, getuid.2, getunwind.2, idle.2, init_module.2, intro.2, iopl.2, kcmp.2, kexec_load.2, kill.2, link.2, linkat.2, llseek.2, lookup_dcookie.2, madvise.2, mincore.2, mkdirat.2, mknodat.2, mmap.2, mmap2.2, mount.2, mprotect.2, mq_getsetattr.2, msgctl.2, msgget.2, msgop.2, msync.2, nice.2, open.2, openat.2, pause.2, perfmonctl.2, personality.2, pipe.2, poll.2, posix_fadvise.2, prctl.2, pread.2, process_vm_readv.2, quotactl.2, read.2, readahead.2, readdir.2, readlinkat.2, readv.2, reboot.2, recvmmsg.2, remap_file_pages.2, rename.2, renameat.2, rmdir.2, rt_sigqueueinfo.2, select.2, select_tut.2, semctl.2, semget.2, semop.2, sendmmsg.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setresuid.2, setuid.2, setup.2, sgetmask.2, shmctl.2, shmget.2, shmop.2, sigaction.2, sigaltstack.2, signal.2, sigpending.2, sigprocmask.2, sigreturn.2, sigsuspend.2, sigwaitinfo.2, splice.2, stat.2, statfs.2, stime.2, subpage_prot.2, swapon.2, symlink.2, symlinkat.2, sync.2, sync_file_range.2, syscalls.2, sysctl.2, sysfs.2, syslog.2, tee.2, time.2, timer_create.2, timer_delete.2, timer_getoverrun.2, timer_settime.2, times.2, tkill.2, umask.2, umount.2, uname.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, abort.3, abs.3, acos.3, acosh.3, adjtime.3, aio_init.3, asin.3, asinh.3, asprintf.3, assert.3, assert_perror.3, atan.3, atan2.3, atanh.3, atexit.3, atof.3, atoi.3, basename.3, bcmp.3, bcopy.3, bindresvport.3, bsd_signal.3, bsearch.3, bstring.3, byteorder.3, bzero.3, catgets.3, catopen.3, cbrt.3, ceil.3, clearenv.3, clock.3, clock_getcpuclockid.3, closedir.3, confstr.3, copysign.3, cos.3, cosh.3, ctermid.3, ctime.3, difftime.3, dirfd.3, div.3, dl_iterate_phdr.3, dprintf.3, drand48.3, drand48_r.3, dysize.3, ecvt.3, ecvt_r.3, end.3, endian.3, erf.3, erfc.3, ether_aton.3, euidaccess.3, exit.3, exp.3, exp10.3, exp2.3, expm1.3, fabs.3, fcloseall.3, fexecve.3, ffs.3, fgetgrent.3, fgetpwent.3, finite.3, flockfile.3, floor.3, fmod.3, fnmatch.3, fopencookie.3, fpathconf.3, fpurge.3, frexp.3, fseeko.3, ftok.3, futimes.3, gcvt.3, get_nprocs_conf.3, getaddrinfo.3, getaddrinfo_a.3, getauxval.3, getcontext.3, getcwd.3, getdate.3, getdirentries.3, getdtablesize.3, getenv.3, getfsent.3, getgrent.3, getgrnam.3, getgrouplist.3, gethostbyname.3, gethostid.3, getifaddrs.3, getipnodebyname.3, getline.3, getlogin.3, getmntent.3, getnetent.3, getnetent_r.3, getopt.3, getprotoent.3, getprotoent_r.3, getpw.3, getpwent.3, getpwnam.3, getrpcent_r.3, gets.3, getservent.3, getservent_r.3, getumask.3, getusershell.3, getutmp.3, getw.3, glob.3, gnu_get_libc_version.3, gsignal.3, hypot.3, if_nameindex.3, if_nametoindex.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, j0.3, ldexp.3, localeconv.3, log.3, log10.3, log1p.3, log2.3, logb.3, lrint.3, lround.3, lsearch.3, lseek64.3, makecontext.3, makedev.3, mallinfo.3, malloc.3, malloc_get_state.3, malloc_info.3, malloc_stats.3, malloc_trim.3, malloc_usable_size.3, mallopt.3, matherr.3, mcheck.3, memccpy.3, memchr.3, memcmp.3, memcpy.3, memfrob.3, memmem.3, memmove.3, memset.3, mkdtemp.3, mkfifo.3, mkfifoat.3, mkstemp.3, mktemp.3, modf.3, mq_close.3, mq_getattr.3, mq_notify.3, mq_open.3, mq_receive.3, mq_send.3, mq_unlink.3, mtrace.3, on_exit.3, opendir.3, posix_fallocate.3, posix_memalign.3, posix_openpt.3, pow.3, pow10.3, profil.3, psignal.3, pthread_attr_init.3, pthread_attr_setaffinity_np.3, pthread_attr_setdetachstate.3, pthread_attr_setguardsize.3, pthread_attr_setinheritsched.3, pthread_attr_setschedparam.3, pthread_attr_setschedpolicy.3, pthread_attr_setscope.3, pthread_attr_setstack.3, pthread_attr_setstackaddr.3, pthread_attr_setstacksize.3, pthread_cancel.3, pthread_cleanup_push.3, pthread_cleanup_push_defer_np.3, pthread_create.3, pthread_detach.3, pthread_equal.3, pthread_exit.3, pthread_getattr_np.3, pthread_getcpuclockid.3, pthread_join.3, pthread_kill.3, pthread_kill_other_threads_np.3, pthread_self.3, pthread_setaffinity_np.3, pthread_setcancelstate.3, pthread_setconcurrency.3, pthread_setname_np.3, pthread_setschedparam.3, pthread_setschedprio.3, pthread_sigmask.3, pthread_sigqueue.3, pthread_testcancel.3, pthread_tryjoin_np.3, pthread_yield.3, putenv.3, putpwent.3, puts.3, qecvt.3, qsort.3, raise.3, rand.3, random.3, random_r.3, re_comp.3, readdir.3, realpath.3, regex.3, remainder.3, remove.3, resolver.3, rewinddir.3, rint.3, round.3, scalb.3, scalbln.3, scandir.3, sched_getcpu.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, setenv.3, setlocale.3, setlogmask.3, shm_open.3, siginterrupt.3, sigpause.3, sigqueue.3, sigset.3, sigsetops.3, sigvec.3, sigwait.3, sin.3, sinh.3, sleep.3, sockatmark.3, sqrt.3, statvfs.3, stdio_ext.3, stpcpy.3, strcasecmp.3, strcat.3, strchr.3, strcmp.3, strcoll.3, strcpy.3, strdup.3, strerror.3, strfry.3, strftime.3, string.3, strlen.3, strpbrk.3, strptime.3, strsep.3, strsignal.3, strspn.3, strstr.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, timegm.3, timeradd.3, tmpfile.3, tmpnam.3, toascii.3, toupper.3, trunc.3, tsearch.3, ttyslot.3, tzset.3, ulimit.3, undocumented.3, unlocked_stdio.3, usleep.3, y0.3, cpuid.4, full.4, initrd.4, mouse.4, msr.4, sd.4, st.4, acct.5, core.5, services.5, slabinfo.5, aio.7, capabilities.7, credentials.7, feature_test_macros.7, hier.7, inotify.7, libc.7, locale.7, man-pages.7, man.7, math_error.7, mq_overview.7, numa.7, path_resolution.7, pipe.7, pthreads.7, pty.7, rtld-audit.7, sem_overview.7, shm_overview.7, sigevent.7, signal.7, suffixes.7, svipc.7, termio.7, time.7, udplite.7, units.7, uri.7, sln.8: s/LICENSE_START(verbatim)/LICENSE_START(VERBATIM)/
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2013-03-10 09:29:01 +00:00
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.\" %%%LICENSE_START(VERBATIM)
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2004-11-03 13:51:07 +00:00
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.\" Permission is granted to make and distribute verbatim copies of this
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.\" manual provided the copyright notice and this permission notice are
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.\" preserved on all copies.
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.\"
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.\" Permission is granted to copy and distribute modified versions of this
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.\" manual under the conditions for verbatim copying, provided that the
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.\" entire resulting derived work is distributed under the terms of a
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.\" permission notice identical to this one.
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2007-04-12 22:42:49 +00:00
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.\"
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2004-11-03 13:51:07 +00:00
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.\" Since the Linux kernel and libraries are constantly changing, this
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.\" manual page may be incorrect or out-of-date. The author(s) assume no
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.\" responsibility for errors or omissions, or for damages resulting from
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.\" the use of the information contained herein. The author(s) may not
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.\" have taken the same level of care in the production of this manual,
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.\" which is licensed free of charge, as they might when working
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.\" professionally.
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2007-04-12 22:42:49 +00:00
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.\"
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2004-11-03 13:51:07 +00:00
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.\" Formatted or processed versions of this manual, if unaccompanied by
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.\" the source, must acknowledge the copyright and authors of this work.
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intro.1, _exit.2, access.2, alarm.2, alloc_hugepages.2, arch_prctl.2, bind.2, chdir.2, chmod.2, chown.2, chroot.2, clock_getres.2, clock_nanosleep.2, close.2, connect.2, delete_module.2, dup.2, execve.2, exit_group.2, faccessat.2, fchmodat.2, fchownat.2, fcntl.2, fork.2, fstatat.2, fsync.2, futimesat.2, get_robust_list.2, getdents.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getpagesize.2, getpid.2, getresuid.2, getrlimit.2, getrusage.2, gettid.2, gettimeofday.2, getuid.2, getunwind.2, idle.2, init_module.2, intro.2, iopl.2, kcmp.2, kexec_load.2, kill.2, link.2, linkat.2, llseek.2, lookup_dcookie.2, madvise.2, mincore.2, mkdirat.2, mknodat.2, mmap.2, mmap2.2, mount.2, mprotect.2, mq_getsetattr.2, msgctl.2, msgget.2, msgop.2, msync.2, nice.2, open.2, openat.2, pause.2, perfmonctl.2, personality.2, pipe.2, poll.2, posix_fadvise.2, prctl.2, pread.2, process_vm_readv.2, quotactl.2, read.2, readahead.2, readdir.2, readlinkat.2, readv.2, reboot.2, recvmmsg.2, remap_file_pages.2, rename.2, renameat.2, rmdir.2, rt_sigqueueinfo.2, select.2, select_tut.2, semctl.2, semget.2, semop.2, sendmmsg.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setresuid.2, setuid.2, setup.2, sgetmask.2, shmctl.2, shmget.2, shmop.2, sigaction.2, sigaltstack.2, signal.2, sigpending.2, sigprocmask.2, sigreturn.2, sigsuspend.2, sigwaitinfo.2, splice.2, stat.2, statfs.2, stime.2, subpage_prot.2, swapon.2, symlink.2, symlinkat.2, sync.2, sync_file_range.2, syscalls.2, sysctl.2, sysfs.2, syslog.2, tee.2, time.2, timer_create.2, timer_delete.2, timer_getoverrun.2, timer_settime.2, times.2, tkill.2, umask.2, umount.2, uname.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, abort.3, abs.3, acos.3, acosh.3, adjtime.3, aio_init.3, asin.3, asinh.3, asprintf.3, assert.3, assert_perror.3, atan.3, atan2.3, atanh.3, atexit.3, atof.3, atoi.3, basename.3, bcmp.3, bcopy.3, bindresvport.3, bsd_signal.3, bsearch.3, bstring.3, byteorder.3, bzero.3, catgets.3, catopen.3, cbrt.3, ceil.3, clearenv.3, clock.3, clock_getcpuclockid.3, closedir.3, confstr.3, copysign.3, cos.3, cosh.3, ctermid.3, ctime.3, difftime.3, dirfd.3, div.3, dl_iterate_phdr.3, dprintf.3, drand48.3, drand48_r.3, dysize.3, ecvt.3, ecvt_r.3, end.3, endian.3, erf.3, erfc.3, ether_aton.3, euidaccess.3, exit.3, exp.3, exp10.3, exp2.3, expm1.3, fabs.3, fcloseall.3, fexecve.3, ffs.3, fgetgrent.3, fgetpwent.3, finite.3, flockfile.3, floor.3, fmod.3, fnmatch.3, fopencookie.3, fpathconf.3, fpurge.3, frexp.3, fseeko.3, ftok.3, futimes.3, gcvt.3, get_nprocs_conf.3, getaddrinfo.3, getaddrinfo_a.3, getauxval.3, getcontext.3, getcwd.3, getdate.3, getdirentries.3, getdtablesize.3, getenv.3, getfsent.3, getgrent.3, getgrnam.3, getgrouplist.3, gethostbyname.3, gethostid.3, getifaddrs.3, getipnodebyname.3, getline.3, getlogin.3, getmntent.3, getnetent.3, getnetent_r.3, getopt.3, getprotoent.3, getprotoent_r.3, getpw.3, getpwent.3, getpwnam.3, getrpcent_r.3, gets.3, getservent.3, getservent_r.3, getumask.3, getusershell.3, getutmp.3, getw.3, glob.3, gnu_get_libc_version.3, gsignal.3, hypot.3, if_nameindex.3, if_nametoindex.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, j0.3, ldexp.3, localeconv.3, log.3, log10.3, log1p.3, log2.3, logb.3, lrint.3, lround.3, lsearch.3, lseek64.3, makecontext.3, makedev.3, mallinfo.3, malloc.3, malloc_get_state.3, malloc_info.3, malloc_stats.3, malloc_trim.3, malloc_usable_size.3, mallopt.3, matherr.3, mcheck.3, memccpy.3, memchr.3, memcmp.3, memcpy.3, memfrob.3, memmem.3, memmove.3, memset.3, mkdtemp.3, mkfifo.3, mkfifoat.3, mkstemp.3, mktemp.3, modf.3, mq_close.3, mq_getattr.3, mq_notify.3, mq_open.3, mq_receive.3, mq_send.3, mq_unlink.3, mtrace.3, on_exit.3, opendir.3, posix_fallocate.3, posix_memalign.3, posix_openpt.3, pow.3, pow10.3, profil.3, psignal.3, pthread_attr_init.3, pthread_attr_setaffinity_np.3, pthread_attr_setdetachstate.3, pthread_attr_setguardsize.3, pthread_attr_setinheritsched.3, pthread_attr_setschedparam.3, pthread_attr_setschedpolicy.3, pthread_attr_setscope.3, pthread_attr_setstack.3, pthread_attr_setstackaddr.3, pthread_attr_setstacksize.3, pthread_cancel.3, pthread_cleanup_push.3, pthread_cleanup_push_defer_np.3, pthread_create.3, pthread_detach.3, pthread_equal.3, pthread_exit.3, pthread_getattr_np.3, pthread_getcpuclockid.3, pthread_join.3, pthread_kill.3, pthread_kill_other_threads_np.3, pthread_self.3, pthread_setaffinity_np.3, pthread_setcancelstate.3, pthread_setconcurrency.3, pthread_setname_np.3, pthread_setschedparam.3, pthread_setschedprio.3, pthread_sigmask.3, pthread_sigqueue.3, pthread_testcancel.3, pthread_tryjoin_np.3, pthread_yield.3, putenv.3, putpwent.3, puts.3, qecvt.3, qsort.3, raise.3, rand.3, random.3, random_r.3, re_comp.3, readdir.3, realpath.3, regex.3, remainder.3, remove.3, resolver.3, rewinddir.3, rint.3, round.3, scalb.3, scalbln.3, scandir.3, sched_getcpu.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, setenv.3, setlocale.3, setlogmask.3, shm_open.3, siginterrupt.3, sigpause.3, sigqueue.3, sigset.3, sigsetops.3, sigvec.3, sigwait.3, sin.3, sinh.3, sleep.3, sockatmark.3, sqrt.3, statvfs.3, stdio_ext.3, stpcpy.3, strcasecmp.3, strcat.3, strchr.3, strcmp.3, strcoll.3, strcpy.3, strdup.3, strerror.3, strfry.3, strftime.3, string.3, strlen.3, strpbrk.3, strptime.3, strsep.3, strsignal.3, strspn.3, strstr.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, timegm.3, timeradd.3, tmpfile.3, tmpnam.3, toascii.3, toupper.3, trunc.3, tsearch.3, ttyslot.3, tzset.3, ulimit.3, undocumented.3, unlocked_stdio.3, usleep.3, y0.3, cpuid.4, full.4, initrd.4, mouse.4, msr.4, sd.4, st.4, acct.5, core.5, services.5, slabinfo.5, aio.7, capabilities.7, credentials.7, feature_test_macros.7, hier.7, inotify.7, libc.7, locale.7, man-pages.7, man.7, math_error.7, mq_overview.7, numa.7, path_resolution.7, pipe.7, pthreads.7, pty.7, rtld-audit.7, sem_overview.7, shm_overview.7, sigevent.7, signal.7, suffixes.7, svipc.7, termio.7, time.7, udplite.7, units.7, uri.7, sln.8: Global fix: Add LICENSE_START(verbatim)
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2013-03-10 09:28:40 +00:00
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.\" %%%LICENSE_END
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2004-11-03 13:51:07 +00:00
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.\"
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.\" Modified Sat Jul 24 00:06:00 1993 by Rik Faith <faith@cs.unc.edu>
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.\" Modified Wed Jan 17 16:02:32 1996 by Michael Haardt
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.\" <michael@cantor.informatik.rwth-aachen.de>
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.\" Modified Thu Apr 11 19:26:35 1996 by Andries Brouwer <aeb@cwi.nl>
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.\" Modified Sun Jul 21 18:59:33 1996 by Andries Brouwer <aeb@cwi.nl>
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.\" Modified Fri Jan 31 16:47:33 1997 by Eric S. Raymond <esr@thyrsus.com>
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.\" Modified Sat Jul 12 20:45:39 1997 by Michael Haardt
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.\" <michael@cantor.informatik.rwth-aachen.de>
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.\"
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getent.1, ldd.1, locale.1, localedef.1, memusage.1, memusagestat.1, mtrace.1, _exit.2, _syscall.2, accept.2, access.2, acct.2, add_key.2, adjtimex.2, alloc_hugepages.2, arch_prctl.2, bdflush.2, bind.2, bpf.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, close_range.2, connect.2, copy_file_range.2, create_module.2, delete_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, execveat.2, fanotify_init.2, fanotify_mark.2, fcntl.2, flock.2, fork.2, fsync.2, futex.2, get_kernel_syms.2, get_mempolicy.2, get_robust_list.2, getcpu.2, getdents.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpid.2, getpriority.2, getrandom.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_rm_watch.2, io_cancel.2, io_destroy.2, io_getevents.2, io_setup.2, io_submit.2, ioctl.2, ioctl_console.2, ioctl_fat.2, ioctl_ficlonerange.2, ioctl_fideduperange.2, ioctl_fslabel.2, ioctl_getfsmap.2, ioctl_ns.2, ioctl_tty.2, ioctl_userfaultfd.2, ioperm.2, iopl.2, ipc.2, kcmp.2, kexec_load.2, keyctl.2, kill.2, link.2, listen.2, listxattr.2, llseek.2, lookup_dcookie.2, lseek.2, madvise.2, mbind.2, membarrier.2, memfd_create.2, migrate_pages.2, mincore.2, mkdir.2, mknod.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, open_by_handle_at.2, openat2.2, pause.2, pciconfig_read.2, perf_event_open.2, perfmonctl.2, personality.2, pidfd_getfd.2, pidfd_open.2, pidfd_send_signal.2, pipe.2, pivot_root.2, pkey_alloc.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, readv.2, reboot.2, recv.2, remap_file_pages.2, removexattr.2, rename.2, request_key.2, restart_syscall.2, rmdir.2, rt_sigqueueinfo.2, s390_guarded_storage.2, s390_pci_mmio_write.2, s390_runtime_instr.2, s390_sthyi.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setattr.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, seccomp.2, select.2, select_tut.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, set_thread_area.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, setup.2, setxattr.2, sgetmask.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, spu_create.2, spu_run.2, stat.2, statfs.2, statx.2, stime.2, subpage_prot.2, swapon.2, symlink.2, sync.2, sync_file_range.2, syscall.2, syscalls.2, sysctl.2, sysfs.2, sysinfo.2, syslog.2, time.2, timer_create.2, timer_delete.2, timer_getoverrun.2, timer_settime.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, uname.2, unimplemented.2, unlink.2, unshare.2, uselib.2, userfaultfd.2, ustat.2, utime.2, utimensat.2, vfork.2, vhangup.2, vm86.2, vmsplice.2, wait.2, wait4.2, write.2, CPU_SET.3, __ppc_get_timebase.3, __ppc_set_ppr_med.3, __ppc_yield.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, 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, cexp.3, cexp2.3, cfree.3, cimag.3, circleq.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, des_crypt.3, difftime.3, dirfd.3, div.3, dl_iterate_phdr.3, dladdr.3, dlerror.3, dlinfo.3, dlopen.3, dlsym.3, drand48.3, drand48_r.3, duplocale.3, dysize.3, ecvt.3, ecvt_r.3, encrypt.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, fgetc.3, fgetgrent.3, fgetpwent.3, fgetwc.3, fgetws.3, fileno.3, finite.3, flockfile.3, floor.3, fma.3, fmax.3, fmemopen.3, fmin.3, fmod.3, fmtmsg.3, fnmatch.3, fopen.3, fopencookie.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, get_nprocs_conf.3, get_phys_pages.3, getaddrinfo.3, getaddrinfo_a.3, getauxval.3, getcontext.3, getcwd.3, getdate.3, getdirentries.3, getdtablesize.3, getentropy.3, getenv.3, getfsent.3, getgrent.3, getgrent_r.3, getgrnam.3, getgrouplist.3, gethostbyname.3, gethostid.3, getifaddrs.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, getsubopt.3, getttyent.3, getumask.3, getusershell.3, getutent.3, getutmp.3, getw.3, getwchar.3, glob.3, gnu_get_libc_version.3, grantpt.3, group_member.3, gsignal.3, hsearch.3, hypot.3, iconv.3, iconv_close.3, iconv_open.3, if_nameindex.3, if_nametoindex.3, ilogb.3, index.3, inet.3, inet_net_pton.3, inet_ntop.3, inet_pton.3, initgroups.3, insque.3, isalpha.3, isatty.3, isfdtype.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, killpg.3, ldexp.3, lgamma.3, lio_listio.3, list.3, localeconv.3, lockf.3, log.3, log10.3, log1p.3, log2.3, logb.3, login.3, lrint.3, lround.3, lsearch.3, lseek64.3, makecontext.3, makedev.3, mallinfo.3, malloc.3, malloc_get_state.3, malloc_hook.3, malloc_info.3, malloc_stats.3, malloc_trim.3, malloc_usable_size.3, mallopt.3, matherr.3, mblen.3, mbrlen.3, mbrtowc.3, mbsinit.3, mbsnrtowcs.3, mbsrtowcs.3, mbstowcs.3, mbtowc.3, mcheck.3, memccpy.3, memchr.3, memcmp.3, memcpy.3, memfrob.3, memmem.3, memmove.3, mempcpy.3, memset.3, mkdtemp.3, mkfifo.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, newlocale.3, nextafter.3, nextup.3, nl_langinfo.3, ntp_gettime.3, on_exit.3, open_memstream.3, opendir.3, openpty.3, perror.3, popen.3, posix_fallocate.3, posix_madvise.3, posix_memalign.3, posix_openpt.3, posix_spawn.3, pow.3, pow10.3, printf.3, profil.3, psignal.3, pthread_attr_init.3, pthread_attr_setaffinity_np.3, pthread_attr_setdetachstate.3, pthread_attr_setguardsize.3, pthread_attr_setinheritsched.3, pthread_attr_setschedparam.3, pthread_attr_setschedpolicy.3, pthread_attr_setscope.3, pthread_attr_setsigmask_np.3, pthread_attr_setstack.3, pthread_attr_setstackaddr.3, pthread_attr_setstacksize.3, pthread_cancel.3, pthread_cleanup_push.3, pthread_cleanup_push_defer_np.3, pthread_create.3, pthread_detach.3, pthread_equal.3, pthread_exit.3, pthread_getattr_default_np.3, pthread_getattr_np.3, pthread_getcpuclockid.3, pthread_join.3, pthread_kill.3, pthread_kill_other_threads_np.3, pthread_mutex_consistent.3, pthread_mutexattr_getpshared.3, pthread_mutexattr_setrobust.3, pthread_rwlockattr_setkind_np.3, pthread_self.3, pthread_setaffinity_np.3, pthread_setcancelstate.3, pthread_setconcurrency.3, pthread_setname_np.3, pthread_setschedparam.3, pthread_setschedprio.3, pthread_sigmask.3, pthread_sigqueue.3, pthread_spin_init.3, pthread_spin_lock.3, pthread_testcancel.3, pthread_tryjoin_np.3, pthread_yield.3, ptsname.3, putenv.3, putgrent.3, putpwent.3, puts.3, putwchar.3, qecvt.3, qsort.3, raise.3, rand.3, random.3, random_r.3, rcmd.3, re_comp.3, readdir.3, readdir_r.3, realpath.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, scanf.3, sched_getcpu.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, sigwait.3, sin.3, sincos.3, sinh.3, sleep.3, slist.3, sockatmark.3, sqrt.3, stailq.3, statvfs.3, stdarg.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, strfromd.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, tailq.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, undocumented.3, ungetwc.3, unlocked_stdio.3, unlockpt.3, updwtmp.3, uselocale.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_codes.4, dsp56k.4, hpsa.4, initrd.4, loop.4, lp.4, msr.4, random.4, rtc.4, smartpqi.4, veth.4, wavelan.4, acct.5, core.5, elf.5, hosts.5, locale.5, proc.5, resolv.conf.5, rpc.5, slabinfo.5, sysfs.5, tmpfs.5, utmp.5, address_families.7, aio.7, attributes.7, bootparam.7, capabilities.7, cgroups.7, complex.7, ddp.7, environ.7, epoll.7, fanotify.7, feature_test_macros.7, hier.7, inode.7, inotify.7, ip.7, ipv6.7, keyrings.7, locale.7, man-pages.7, man.7, math_error.7, mount_namespaces.7, namespaces.7, netdevice.7, netlink.7, numa.7, packet.7, pkeys.7, pthreads.7, queue.7, raw.7, rtnetlink.7, sched.7, session-keyring.7, shm_overview.7, sigevent.7, signal-safety.7, signal.7, sock_diag.7, socket.7, spufs.7, symlink.7, system_data_types.7, tcp.7, time_namespaces.7, udp.7, udplite.7, unicode.7, unix.7, uri.7, user_namespaces.7, vdso.7, vsock.7, x25.7, iconvconfig.8, ld.so.8, ldconfig.8, sln.8, tzselect.8: tstamp
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2021-03-21 23:15:34 +00:00
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.TH READ 2 2021-03-22 "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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read \- read from a file descriptor
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.SH SYNOPSIS
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.nf
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.B #include <unistd.h>
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_exit.2, bpf.2, cacheflush.2, capget.2, chdir.2, chmod.2, chroot.2, clock_getres.2, clock_nanosleep.2, close.2, connect.2, create_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, execveat.2, exit_group.2, fanotify_mark.2, flock.2, fork.2, fsync.2, futex.2, futimesat.2, get_kernel_syms.2, get_mempolicy.2, get_robust_list.2, getcpu.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpid.2, getpriority.2, getrandom.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, inotify_add_watch.2, inotify_init.2, inotify_rm_watch.2, ioctl.2, ioctl_fat.2, ioctl_ficlonerange.2, ioctl_fideduperange.2, ioctl_getfsmap.2, ioctl_tty.2, ioperm.2, iopl.2, keyctl.2, kill.2, link.2, listen.2, listxattr.2, llseek.2, lseek.2, madvise.2, mbind.2, membarrier.2, memfd_create.2, migrate_pages.2, mincore.2, mkdir.2, mknod.2, mlock.2, mmap.2, mmap2.2, modify_ldt.2, mount.2, move_pages.2, mprotect.2, mq_getsetattr.2, mremap.2, msgop.2, msync.2, nanosleep.2, nfsservctl.2, nice.2, pause.2, pciconfig_read.2, perf_event_open.2, perfmonctl.2, personality.2, pkey_alloc.2, poll.2, posix_fadvise.2, prctl.2, pread.2, process_vm_readv.2, ptrace.2, query_module.2, read.2, readahead.2, readdir.2, readv.2, reboot.2, recv.2, remap_file_pages.2, removexattr.2, rename.2, request_key.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, select_tut.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, set_mempolicy.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setns.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, setup.2, setxattr.2, sgetmask.2, shmctl.2, shmget.2, shutdown.2, sigaction.2, sigaltstack.2, sigpending.2, sigprocmask.2, sigsuspend.2, sigwaitinfo.2, socket.2, socketcall.2, socketpair.2, stat.2, statfs.2, stime.2, swapon.2, symlink.2, sync.2, sysctl.2, sysinfo.2, syslog.2, time.2, timer_create.2, timer_delete.2, timer_getoverrun.2, timer_settime.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, uname.2, unlink.2, unshare.2, uselib.2, userfaultfd.2, ustat.2, utime.2, utimensat.2, vfork.2, vhangup.2, vm86.2, wait.2, wait4.2, write.2, CPU_SET.3, INFINITY.3, __ppc_get_timebase.3, __ppc_set_ppr_med.3, __ppc_yield.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_init.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, basename.3, bcmp.3, bcopy.3, bsd_signal.3, bsearch.3, bstring.3, btowc.3, byteorder.3, cabs.3, cacos.3, cacosh.3, canonicalize_file_name.3, carg.3, casin.3, casinh.3, catan.3, catanh.3, catopen.3, cbrt.3, ccos.3, ccosh.3, ceil.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, difftime.3, dirfd.3, div.3, dlerror.3, dlopen.3, dlsym.3, drand48.3, drand48_r.3, duplocale.3, dysize.3, ecvt.3, ecvt_r.3, encrypt.3, endian.3, erf.3, erfc.3, err.3, errno.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, fgetc.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, get_nprocs_conf.3, get_phys_pages.3, getaddrinfo.3, getaddrinfo_a.3, getauxval.3, getcontext.3, getcwd.3, getdate.3, getdirentries.3, getdtablesize.3, getentropy.3, getenv.3, getfsent.3, getgrent.3, getgrent_r.3, getgrnam.3, getgrouplist.3, gethostbyname.3, gethostid.3, getifaddrs.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_r.3, getrpcport.3, gets.3, getservent.3, getservent_r.3, getspnam.3, getsubopt.3, getttyent.3, getumask.3, getusershell.3, getutent.3, getw.3, getwchar.3, glob.3, grantpt.3, group_member.3, gsignal.3, hsearch.3, hypot.3, iconv.3, iconv_close.3, iconv_open.3, if_nameindex.3, if_nametoindex.3, ilogb.3, index.3, inet.3, inet_net_pton.3, inet_ntop.3, infnan.3, initgroups.3, insque.3, isalpha.3, isatty.3, isfdtype.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, killpg.3, ldexp.3, lgamma.3, localeconv.3, lockf.3, log.3, log10.3, log1p.3, log2.3, logb.3, login.3, lrint.3, lround.3, lsearch.3, lseek64.3, makecontext.3, malloc.3, malloc_get_state.3, malloc_hook.3, malloc_info.3, matherr.3, mblen.3, mbrlen.3, mbrtowc.3, mbsinit.3, mbsnrtowcs.3, mbsrtowcs.3, mbstowcs.3, mbtowc.3, mcheck.3, memccpy.3, memchr.3, memcmp.3, memcpy.3, memfrob.3, memmem.3, memmove.3, mempcpy.3, memset.3, mkdtemp.3, mkfifo.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, newlocale.3, nextafter.3, nl_langinfo.3, offsetof.3, on_exit.3, open_memstream.3, opendir.3, openpty.3, perror.3, popen.3, posix_fallocate.3, posix_madvise.3, posix_memalign.3, posix_openpt.3, pow.3, pow10.3, printf.3, profil.3, psignal.3, pthread_atfork.3, pthread_attr_init.3, pthread_attr_setaffinity_np.3, pthread_attr_setdetachstate.3, pthread_attr_setguardsize.3, pthread_attr_setinheritsched.3, pthread_attr_setschedparam.3, pthread_attr_setschedpolicy.3, pthread_attr_setscope.3, pthread_attr_setstack.3, pthread_attr_setstackaddr.3, pthread_attr_setstacksize.3, pthread_cancel.3, pthread_cleanup_push.3, pthread_cleanup_push_defer_np.3, pthread_create.3, pthread_detach.3, pthread_equal.3, pthread_exit.3, pthread_getattr_default_np.3, pthread_getattr_np.3, pthread_getcpuclockid.3, pthread_join.3, pthread_kill.3, pthread_rwlockattr_setkind_np.3, pthread_self.3, pthread_setaffinity_np.3, pthread_setcancelstate.3, pthread_setconcurrency.3, pthread_setname_np.3, pthread_setschedparam.3, pthread_setschedprio.3, pthread_sigmask.3, pthread_sigqueue.3, pthread_testcancel.3, pthread_tryjoin_np.3, pthread_yield.3, ptsname.3, putenv.3, putgrent.3, putpwent.3, puts.3, putwchar.3, qecvt.3, qsort.3, raise.3, rand.3, random.3, random_r.3, rcmd.3, re_comp.3, readdir.3, realpath.3, remainder.3, remove.3, remquo.3, resolver.3, rewinddir.3, rexec.3, rint.3, round.3, rpmatch.3, rtime.3, rtnetlink.3, scalb.3, scalbln.3, scandir.3, scanf.3, sched_getcpu.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, setlocale.3, setlogmask.3, setnetgrent.3, shm_open.3, siginterrupt.3, signbit.3, significand.3, sigpause.3, sigqueue.3, sigset.3, sigvec.3, sigwait.3, sin.3, sincos.3, sinh.3, sleep.3, sockatmark.3, sqrt.3, statvfs.3, stdarg.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, strfromd.3, strfry.3, strftime.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, uselocale.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, y0.3, dsp56k.4, random.4, rtc.4, st.4, ddp.7, ip.7, ipv6.7, packet.7, rtnetlink.7, socket.7, tcp.7, udp.7, udplite.7, x25.7: ffix
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-15 15:16:29 +00:00
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.PP
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2004-11-03 13:51:07 +00:00
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.BI "ssize_t read(int " fd ", void *" buf ", size_t " count );
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.fi
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.SH DESCRIPTION
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2005-10-19 07:07:02 +00:00
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.BR read ()
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2004-11-03 13:51:07 +00:00
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attempts to read up to
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.I count
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bytes from file descriptor
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.I fd
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into the buffer starting at
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.IR buf .
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_syscall.2, bpf.2, cacheflush.2, capget.2, chdir.2, chmod.2, chroot.2, clock_getres.2, clock_nanosleep.2, clone.2, close.2, connect.2, copy_file_range.2, create_module.2, delete_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, execveat.2, fallocate.2, flock.2, fork.2, fsync.2, futex.2, futimesat.2, get_kernel_syms.2, get_mempolicy.2, get_robust_list.2, getcpu.2, getdents.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpriority.2, getrandom.2, getresuid.2, getrlimit.2, getrusage.2, getsid.2, getsockname.2, getsockopt.2, gettid.2, gettimeofday.2, getuid.2, getunwind.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_fat.2, ioctl_ficlonerange.2, ioctl_fideduperange.2, ioctl_tty.2, ioctl_userfaultfd.2, ioperm.2, iopl.2, ioprio_set.2, kcmp.2, kexec_load.2, keyctl.2, kill.2, link.2, listen.2, listxattr.2, llseek.2, lookup_dcookie.2, lseek.2, madvise.2, mbind.2, membarrier.2, memfd_create.2, migrate_pages.2, mincore.2, mkdir.2, mknod.2, mlock.2, mmap.2, mmap2.2, modify_ldt.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_by_handle_at.2, outb.2, perf_event_open.2, perfmonctl.2, personality.2, pivot_root.2, pkey_alloc.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, readv.2, reboot.2, recv.2, recvmmsg.2, remap_file_pages.2, rename.2, request_key.2, restart_syscall.2, rt_sigqueueinfo.2, s390_pci_mmio_write.2, s390_runtime_instr.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setattr.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, seccomp.2, select.2, select_tut.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, sendmmsg.2, set_mempolicy.2, set_thread_area.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setns.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, sgetmask.2, shmctl.2, shmget.2, shmop.2, sigaction.2, sigaltstack.2, sigpending.2, sigprocmask.2, sigreturn.2, sigsuspend.2, sigwaitinfo.2, socket.2, socketcall.2, socketpair.2, splice.2, spu_create.2, spu_run.2, stat.2, statfs.2, statx.2, subpage_prot.2, swapon.2, symlink.2, sync.2, sync_file_range.2, syscalls.2, sysctl.2, sysinfo.2, syslog.2, tee.2, time.2, timer_create.2, timer_getoverrun.2, timer_settime.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, unimplemented.2, unlink.2, unshare.2, uselib.2, userfaultfd.2, utime.2, utimensat.2, vfork.2, vmsplice.2, wait.2, wait4.2, write.2: Formatting fix: replace blank lines with .PP/.IP
Blank lines shouldn't generally appear in *roff source (other
than in code examples), since they create large vertical
spaces between text blocks.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-16 07:30:51 +00:00
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.PP
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2013-02-12 21:25:08 +00:00
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On files that support seeking,
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2016-01-26 09:13:47 +00:00
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the read operation commences at the file offset,
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2013-02-12 21:25:08 +00:00
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and the file offset is incremented by the number of bytes read.
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2016-01-26 09:13:47 +00:00
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If the file offset is at or past the end of file,
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2013-02-12 21:25:08 +00:00
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no bytes are read, and
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.BR read ()
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returns zero.
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_syscall.2, bpf.2, cacheflush.2, capget.2, chdir.2, chmod.2, chroot.2, clock_getres.2, clock_nanosleep.2, clone.2, close.2, connect.2, copy_file_range.2, create_module.2, delete_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, execveat.2, fallocate.2, flock.2, fork.2, fsync.2, futex.2, futimesat.2, get_kernel_syms.2, get_mempolicy.2, get_robust_list.2, getcpu.2, getdents.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpriority.2, getrandom.2, getresuid.2, getrlimit.2, getrusage.2, getsid.2, getsockname.2, getsockopt.2, gettid.2, gettimeofday.2, getuid.2, getunwind.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_fat.2, ioctl_ficlonerange.2, ioctl_fideduperange.2, ioctl_tty.2, ioctl_userfaultfd.2, ioperm.2, iopl.2, ioprio_set.2, kcmp.2, kexec_load.2, keyctl.2, kill.2, link.2, listen.2, listxattr.2, llseek.2, lookup_dcookie.2, lseek.2, madvise.2, mbind.2, membarrier.2, memfd_create.2, migrate_pages.2, mincore.2, mkdir.2, mknod.2, mlock.2, mmap.2, mmap2.2, modify_ldt.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_by_handle_at.2, outb.2, perf_event_open.2, perfmonctl.2, personality.2, pivot_root.2, pkey_alloc.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, readv.2, reboot.2, recv.2, recvmmsg.2, remap_file_pages.2, rename.2, request_key.2, restart_syscall.2, rt_sigqueueinfo.2, s390_pci_mmio_write.2, s390_runtime_instr.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setattr.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, seccomp.2, select.2, select_tut.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, sendmmsg.2, set_mempolicy.2, set_thread_area.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setns.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, sgetmask.2, shmctl.2, shmget.2, shmop.2, sigaction.2, sigaltstack.2, sigpending.2, sigprocmask.2, sigreturn.2, sigsuspend.2, sigwaitinfo.2, socket.2, socketcall.2, socketpair.2, splice.2, spu_create.2, spu_run.2, stat.2, statfs.2, statx.2, subpage_prot.2, swapon.2, symlink.2, sync.2, sync_file_range.2, syscalls.2, sysctl.2, sysinfo.2, syslog.2, tee.2, time.2, timer_create.2, timer_getoverrun.2, timer_settime.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, unimplemented.2, unlink.2, unshare.2, uselib.2, userfaultfd.2, utime.2, utimensat.2, vfork.2, vmsplice.2, wait.2, wait4.2, write.2: Formatting fix: replace blank lines with .PP/.IP
Blank lines shouldn't generally appear in *roff source (other
than in code examples), since they create large vertical
spaces between text blocks.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-16 07:30:51 +00:00
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.PP
|
2004-11-03 13:51:07 +00:00
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|
If
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|
|
.I count
|
2007-05-12 09:06:04 +00:00
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|
|
is zero,
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|
|
|
|
.BR read ()
|
2013-02-12 21:30:02 +00:00
|
|
|
.I may
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|
|
|
detect the errors described below.
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|
|
In the absence of any errors,
|
2013-03-04 10:22:28 +00:00
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|
|
or if
|
2013-02-12 21:30:02 +00:00
|
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|
.BR read ()
|
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|
does not check for errors, a
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.BR read ()
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with a
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.I count
|
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|
of 0 returns zero and has no other effects.
|
_syscall.2, bpf.2, cacheflush.2, capget.2, chdir.2, chmod.2, chroot.2, clock_getres.2, clock_nanosleep.2, clone.2, close.2, connect.2, copy_file_range.2, create_module.2, delete_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, execveat.2, fallocate.2, flock.2, fork.2, fsync.2, futex.2, futimesat.2, get_kernel_syms.2, get_mempolicy.2, get_robust_list.2, getcpu.2, getdents.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpriority.2, getrandom.2, getresuid.2, getrlimit.2, getrusage.2, getsid.2, getsockname.2, getsockopt.2, gettid.2, gettimeofday.2, getuid.2, getunwind.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_fat.2, ioctl_ficlonerange.2, ioctl_fideduperange.2, ioctl_tty.2, ioctl_userfaultfd.2, ioperm.2, iopl.2, ioprio_set.2, kcmp.2, kexec_load.2, keyctl.2, kill.2, link.2, listen.2, listxattr.2, llseek.2, lookup_dcookie.2, lseek.2, madvise.2, mbind.2, membarrier.2, memfd_create.2, migrate_pages.2, mincore.2, mkdir.2, mknod.2, mlock.2, mmap.2, mmap2.2, modify_ldt.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_by_handle_at.2, outb.2, perf_event_open.2, perfmonctl.2, personality.2, pivot_root.2, pkey_alloc.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, readv.2, reboot.2, recv.2, recvmmsg.2, remap_file_pages.2, rename.2, request_key.2, restart_syscall.2, rt_sigqueueinfo.2, s390_pci_mmio_write.2, s390_runtime_instr.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setattr.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, seccomp.2, select.2, select_tut.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, sendmmsg.2, set_mempolicy.2, set_thread_area.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setns.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, sgetmask.2, shmctl.2, shmget.2, shmop.2, sigaction.2, sigaltstack.2, sigpending.2, sigprocmask.2, sigreturn.2, sigsuspend.2, sigwaitinfo.2, socket.2, socketcall.2, socketpair.2, splice.2, spu_create.2, spu_run.2, stat.2, statfs.2, statx.2, subpage_prot.2, swapon.2, symlink.2, sync.2, sync_file_range.2, syscalls.2, sysctl.2, sysinfo.2, syslog.2, tee.2, time.2, timer_create.2, timer_getoverrun.2, timer_settime.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, unimplemented.2, unlink.2, unshare.2, uselib.2, userfaultfd.2, utime.2, utimensat.2, vfork.2, vmsplice.2, wait.2, wait4.2, write.2: Formatting fix: replace blank lines with .PP/.IP
Blank lines shouldn't generally appear in *roff source (other
than in code examples), since they create large vertical
spaces between text blocks.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-16 07:30:51 +00:00
|
|
|
.PP
|
2017-01-25 23:05:34 +00:00
|
|
|
According to POSIX.1, if
|
2004-11-03 13:51:07 +00:00
|
|
|
.I count
|
2007-06-22 17:16:20 +00:00
|
|
|
is greater than
|
|
|
|
|
.BR SSIZE_MAX ,
|
2017-01-25 23:05:34 +00:00
|
|
|
the result is implementation-defined;
|
|
|
|
|
see NOTES for the upper limit on Linux.
|
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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2004-11-03 13:51:07 +00:00
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On success, the number of bytes read is returned (zero indicates end of
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file), and the file position is advanced by this number.
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It is not an error if this number is smaller than the number of bytes
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requested; this may happen for example because fewer bytes are actually
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available right now (maybe because we were close to end-of-file, or
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because we are reading from a pipe, or from a terminal), or because
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2007-05-12 09:06:04 +00:00
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.BR read ()
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was interrupted by a signal.
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2015-05-11 13:13:56 +00:00
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See also NOTES.
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_syscall.2, bpf.2, cacheflush.2, capget.2, chdir.2, chmod.2, chroot.2, clock_getres.2, clock_nanosleep.2, clone.2, close.2, connect.2, copy_file_range.2, create_module.2, delete_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, execveat.2, fallocate.2, flock.2, fork.2, fsync.2, futex.2, futimesat.2, get_kernel_syms.2, get_mempolicy.2, get_robust_list.2, getcpu.2, getdents.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpriority.2, getrandom.2, getresuid.2, getrlimit.2, getrusage.2, getsid.2, getsockname.2, getsockopt.2, gettid.2, gettimeofday.2, getuid.2, getunwind.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_fat.2, ioctl_ficlonerange.2, ioctl_fideduperange.2, ioctl_tty.2, ioctl_userfaultfd.2, ioperm.2, iopl.2, ioprio_set.2, kcmp.2, kexec_load.2, keyctl.2, kill.2, link.2, listen.2, listxattr.2, llseek.2, lookup_dcookie.2, lseek.2, madvise.2, mbind.2, membarrier.2, memfd_create.2, migrate_pages.2, mincore.2, mkdir.2, mknod.2, mlock.2, mmap.2, mmap2.2, modify_ldt.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_by_handle_at.2, outb.2, perf_event_open.2, perfmonctl.2, personality.2, pivot_root.2, pkey_alloc.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, readv.2, reboot.2, recv.2, recvmmsg.2, remap_file_pages.2, rename.2, request_key.2, restart_syscall.2, rt_sigqueueinfo.2, s390_pci_mmio_write.2, s390_runtime_instr.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setattr.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, seccomp.2, select.2, select_tut.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, sendmmsg.2, set_mempolicy.2, set_thread_area.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setns.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, sgetmask.2, shmctl.2, shmget.2, shmop.2, sigaction.2, sigaltstack.2, sigpending.2, sigprocmask.2, sigreturn.2, sigsuspend.2, sigwaitinfo.2, socket.2, socketcall.2, socketpair.2, splice.2, spu_create.2, spu_run.2, stat.2, statfs.2, statx.2, subpage_prot.2, swapon.2, symlink.2, sync.2, sync_file_range.2, syscalls.2, sysctl.2, sysinfo.2, syslog.2, tee.2, time.2, timer_create.2, timer_getoverrun.2, timer_settime.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, unimplemented.2, unlink.2, unshare.2, uselib.2, userfaultfd.2, utime.2, utimensat.2, vfork.2, vmsplice.2, wait.2, wait4.2, write.2: Formatting fix: replace blank lines with .PP/.IP
Blank lines shouldn't generally appear in *roff source (other
than in code examples), since they create large vertical
spaces between text blocks.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-16 07:30:51 +00:00
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.PP
|
2004-11-03 13:51:07 +00:00
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On error, \-1 is returned, and
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.I errno
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2021-01-07 07:12:28 +00:00
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is set to indicate the error.
|
2014-03-26 05:25:05 +00:00
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In this case, it is left unspecified whether
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2004-11-03 13:51:07 +00:00
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the file position (if any) changes.
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.SH ERRORS
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.TP
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.B EAGAIN
|
2009-02-23 04:57:43 +00:00
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The file descriptor
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.I fd
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accept.2, connect.2, eventfd.2, flock.2, open.2, posix_fadvise.2, read.2, recv.2, sched_setscheduler.2, select_tut.2, send.2, signalfd.2, splice.2, timerfd_create.2, write.2, flockfile.3, mkfifo.3, mq_notify.3, mq_open.3, pthread_tryjoin_np.3, scanf.3, random.4, ddp.7, epoll.7, fifo.7, ip.7, pipe.7, socket.7, spufs.7: Global fix: s/non-blocking/nonblocking/
The tendency in English, as prescribed in style guides like
Chicago MoS, is towards removing hyphens after prefixes
like "non-" etc.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-01-16 16:43:10 +00:00
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refers to a file other than a socket and has been marked nonblocking
|
2009-02-23 04:57:43 +00:00
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.RB ( O_NONBLOCK ),
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|
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and the read would block.
|
2015-05-11 10:03:43 +00:00
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See
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.BR open (2)
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|
for further details on the
|
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.BR O_NONBLOCK
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flag.
|
2009-02-23 04:57:43 +00:00
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.TP
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.BR EAGAIN " or " EWOULDBLOCK
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.\" Actually EAGAIN on Linux
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The file descriptor
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.I fd
|
accept.2, connect.2, eventfd.2, flock.2, open.2, posix_fadvise.2, read.2, recv.2, sched_setscheduler.2, select_tut.2, send.2, signalfd.2, splice.2, timerfd_create.2, write.2, flockfile.3, mkfifo.3, mq_notify.3, mq_open.3, pthread_tryjoin_np.3, scanf.3, random.4, ddp.7, epoll.7, fifo.7, ip.7, pipe.7, socket.7, spufs.7: Global fix: s/non-blocking/nonblocking/
The tendency in English, as prescribed in style guides like
Chicago MoS, is towards removing hyphens after prefixes
like "non-" etc.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-01-16 16:43:10 +00:00
|
|
|
refers to a socket and has been marked nonblocking
|
2009-02-23 04:57:43 +00:00
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.RB ( O_NONBLOCK ),
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and the read would block.
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POSIX.1-2001 allows either error to be returned for this case,
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|
and does not require these constants to have the same value,
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|
so a portable application should check for both possibilities.
|
2004-11-03 13:51:07 +00:00
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|
.TP
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.B EBADF
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.I fd
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is not a valid file descriptor or is not open for reading.
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.TP
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.B EFAULT
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.I buf
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is outside your accessible address space.
|
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.TP
|
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|
.B EINTR
|
2008-07-04 15:50:36 +00:00
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|
|
The call was interrupted by a signal before any data was read; see
|
|
|
|
|
.BR signal (7).
|
2004-11-03 13:51:07 +00:00
|
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|
.TP
|
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|
|
.B EINVAL
|
|
|
|
|
.I fd
|
2005-10-10 13:07:32 +00:00
|
|
|
is attached to an object which is unsuitable for reading;
|
2007-04-12 22:42:49 +00:00
|
|
|
or the file was opened with the
|
2005-10-10 13:07:32 +00:00
|
|
|
.B O_DIRECT
|
|
|
|
|
flag, and either the address specified in
|
|
|
|
|
.IR buf ,
|
|
|
|
|
the value specified in
|
|
|
|
|
.IR count ,
|
2016-01-26 09:13:47 +00:00
|
|
|
or the file offset is not suitably aligned.
|
2004-11-03 13:51:07 +00:00
|
|
|
.TP
|
2007-09-27 17:59:11 +00:00
|
|
|
.B EINVAL
|
|
|
|
|
.I fd
|
|
|
|
|
was created via a call to
|
2007-10-13 20:29:01 +00:00
|
|
|
.BR timerfd_create (2)
|
2007-09-27 17:59:11 +00:00
|
|
|
and the wrong size buffer was given to
|
|
|
|
|
.BR read ();
|
|
|
|
|
see
|
2007-10-13 20:29:01 +00:00
|
|
|
.BR timerfd_create (2)
|
2007-09-27 17:59:11 +00:00
|
|
|
for further information.
|
|
|
|
|
.TP
|
2004-11-03 13:51:07 +00:00
|
|
|
.B EIO
|
2007-04-12 22:42:49 +00:00
|
|
|
I/O error.
|
|
|
|
|
This will happen for example when the process is in a
|
lseek.2, read.2, setsid.2, vhangup.2, getttyent.3, login.3, openpty.3, console_codes.4, console_ioctl.4, securetty.5, signal.7: Global fix: s/tty/terminal/
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2012-12-31 20:54:13 +00:00
|
|
|
background process group, tries to read from its controlling terminal,
|
2007-06-21 05:38:48 +00:00
|
|
|
and either it is ignoring or blocking
|
|
|
|
|
.B SIGTTIN
|
|
|
|
|
or its process group
|
2007-04-12 22:42:49 +00:00
|
|
|
is orphaned.
|
|
|
|
|
It may also occur when there is a low-level I/O error
|
2004-11-03 13:51:07 +00:00
|
|
|
while reading from a disk or tape.
|
2017-12-13 04:19:14 +00:00
|
|
|
A further possible cause of
|
|
|
|
|
.B EIO
|
|
|
|
|
on networked filesystems is when an advisory lock had been taken
|
|
|
|
|
out on the file descriptor and this lock has been lost.
|
|
|
|
|
See the
|
|
|
|
|
.I "Lost locks"
|
|
|
|
|
section of
|
|
|
|
|
.BR fcntl (2)
|
|
|
|
|
for further details.
|
2004-11-03 13:51:07 +00:00
|
|
|
.TP
|
|
|
|
|
.B EISDIR
|
|
|
|
|
.I fd
|
|
|
|
|
refers to a directory.
|
|
|
|
|
.PP
|
|
|
|
|
Other errors may occur, depending on the object connected to
|
|
|
|
|
.IR fd .
|
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
|
|
|
.SH CONFORMING TO
|
2006-08-03 13:57:17 +00:00
|
|
|
SVr4, 4.3BSD, POSIX.1-2001.
|
2007-05-16 05:33:35 +00:00
|
|
|
.SH NOTES
|
2016-04-11 16:03:39 +00:00
|
|
|
The types
|
|
|
|
|
.I size_t
|
|
|
|
|
and
|
|
|
|
|
.I ssize_t
|
|
|
|
|
are, respectively,
|
|
|
|
|
unsigned and signed integer data types specified by POSIX.1.
|
_syscall.2, bpf.2, cacheflush.2, capget.2, chdir.2, chmod.2, chroot.2, clock_getres.2, clock_nanosleep.2, clone.2, close.2, connect.2, copy_file_range.2, create_module.2, delete_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, execveat.2, fallocate.2, flock.2, fork.2, fsync.2, futex.2, futimesat.2, get_kernel_syms.2, get_mempolicy.2, get_robust_list.2, getcpu.2, getdents.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpriority.2, getrandom.2, getresuid.2, getrlimit.2, getrusage.2, getsid.2, getsockname.2, getsockopt.2, gettid.2, gettimeofday.2, getuid.2, getunwind.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_fat.2, ioctl_ficlonerange.2, ioctl_fideduperange.2, ioctl_tty.2, ioctl_userfaultfd.2, ioperm.2, iopl.2, ioprio_set.2, kcmp.2, kexec_load.2, keyctl.2, kill.2, link.2, listen.2, listxattr.2, llseek.2, lookup_dcookie.2, lseek.2, madvise.2, mbind.2, membarrier.2, memfd_create.2, migrate_pages.2, mincore.2, mkdir.2, mknod.2, mlock.2, mmap.2, mmap2.2, modify_ldt.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_by_handle_at.2, outb.2, perf_event_open.2, perfmonctl.2, personality.2, pivot_root.2, pkey_alloc.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, readv.2, reboot.2, recv.2, recvmmsg.2, remap_file_pages.2, rename.2, request_key.2, restart_syscall.2, rt_sigqueueinfo.2, s390_pci_mmio_write.2, s390_runtime_instr.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setattr.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, seccomp.2, select.2, select_tut.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, sendmmsg.2, set_mempolicy.2, set_thread_area.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setns.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, sgetmask.2, shmctl.2, shmget.2, shmop.2, sigaction.2, sigaltstack.2, sigpending.2, sigprocmask.2, sigreturn.2, sigsuspend.2, sigwaitinfo.2, socket.2, socketcall.2, socketpair.2, splice.2, spu_create.2, spu_run.2, stat.2, statfs.2, statx.2, subpage_prot.2, swapon.2, symlink.2, sync.2, sync_file_range.2, syscalls.2, sysctl.2, sysinfo.2, syslog.2, tee.2, time.2, timer_create.2, timer_getoverrun.2, timer_settime.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, unimplemented.2, unlink.2, unshare.2, uselib.2, userfaultfd.2, utime.2, utimensat.2, vfork.2, vmsplice.2, wait.2, wait4.2, write.2: Formatting fix: replace blank lines with .PP/.IP
Blank lines shouldn't generally appear in *roff source (other
than in code examples), since they create large vertical
spaces between text blocks.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-16 07:30:51 +00:00
|
|
|
.PP
|
2015-05-11 13:13:56 +00:00
|
|
|
On Linux,
|
|
|
|
|
.BR read ()
|
|
|
|
|
(and similar system calls) will transfer at most
|
|
|
|
|
0x7ffff000 (2,147,479,552) bytes,
|
|
|
|
|
returning the number of bytes actually transferred.
|
|
|
|
|
.\" commit e28cc71572da38a5a12c1cfe4d7032017adccf69
|
|
|
|
|
(This is true on both 32-bit and 64-bit systems.)
|
_syscall.2, bpf.2, cacheflush.2, capget.2, chdir.2, chmod.2, chroot.2, clock_getres.2, clock_nanosleep.2, clone.2, close.2, connect.2, copy_file_range.2, create_module.2, delete_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, execveat.2, fallocate.2, flock.2, fork.2, fsync.2, futex.2, futimesat.2, get_kernel_syms.2, get_mempolicy.2, get_robust_list.2, getcpu.2, getdents.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpriority.2, getrandom.2, getresuid.2, getrlimit.2, getrusage.2, getsid.2, getsockname.2, getsockopt.2, gettid.2, gettimeofday.2, getuid.2, getunwind.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_fat.2, ioctl_ficlonerange.2, ioctl_fideduperange.2, ioctl_tty.2, ioctl_userfaultfd.2, ioperm.2, iopl.2, ioprio_set.2, kcmp.2, kexec_load.2, keyctl.2, kill.2, link.2, listen.2, listxattr.2, llseek.2, lookup_dcookie.2, lseek.2, madvise.2, mbind.2, membarrier.2, memfd_create.2, migrate_pages.2, mincore.2, mkdir.2, mknod.2, mlock.2, mmap.2, mmap2.2, modify_ldt.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_by_handle_at.2, outb.2, perf_event_open.2, perfmonctl.2, personality.2, pivot_root.2, pkey_alloc.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, readv.2, reboot.2, recv.2, recvmmsg.2, remap_file_pages.2, rename.2, request_key.2, restart_syscall.2, rt_sigqueueinfo.2, s390_pci_mmio_write.2, s390_runtime_instr.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setattr.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, seccomp.2, select.2, select_tut.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, sendmmsg.2, set_mempolicy.2, set_thread_area.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setns.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, sgetmask.2, shmctl.2, shmget.2, shmop.2, sigaction.2, sigaltstack.2, sigpending.2, sigprocmask.2, sigreturn.2, sigsuspend.2, sigwaitinfo.2, socket.2, socketcall.2, socketpair.2, splice.2, spu_create.2, spu_run.2, stat.2, statfs.2, statx.2, subpage_prot.2, swapon.2, symlink.2, sync.2, sync_file_range.2, syscalls.2, sysctl.2, sysinfo.2, syslog.2, tee.2, time.2, timer_create.2, timer_getoverrun.2, timer_settime.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, unimplemented.2, unlink.2, unshare.2, uselib.2, userfaultfd.2, utime.2, utimensat.2, vfork.2, vmsplice.2, wait.2, wait4.2, write.2: Formatting fix: replace blank lines with .PP/.IP
Blank lines shouldn't generally appear in *roff source (other
than in code examples), since they create large vertical
spaces between text blocks.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-16 07:30:51 +00:00
|
|
|
.PP
|
intro.1, time.1, access.2, acct.2, alloc_hugepages.2, bind.2, chdir.2, chmod.2, chown.2, chroot.2, clone.2, close.2, execve.2, fallocate.2, fcntl.2, getdents.2, getrusage.2, getxattr.2, init_module.2, inotify_add_watch.2, ioprio_set.2, kcmp.2, link.2, listxattr.2, lseek.2, madvise.2, mkdir.2, mknod.2, mmap.2, mount.2, move_pages.2, msgctl.2, nfsservctl.2, open.2, pivot_root.2, quotactl.2, read.2, readlink.2, removexattr.2, rename.2, rmdir.2, semctl.2, setfsgid.2, setfsuid.2, setresuid.2, setuid.2, setup.2, setxattr.2, shmctl.2, splice.2, spu_create.2, stat.2, statfs.2, swapon.2, symlink.2, sync.2, sync_file_range.2, sysfs.2, truncate.2, umount.2, unlink.2, unshare.2, ustat.2, utime.2, utimensat.2, write.2, btree.3, errno.3, fexecve.3, ftw.3, futimes.3, get_nprocs_conf.3, getcwd.3, getdirentries.3, getmntent.3, glob.3, mkfifo.3, mq_open.3, readdir.3, realpath.3, recno.3, remove.3, sem_open.3, shm_open.3, statvfs.3, sysconf.3, telldir.3, tmpfile.3, cciss.4, initrd.4, pts.4, sk98lin.4, vcs.4, core.5, filesystems.5, proc.5, boot.7, bootparam.7, capabilities.7, cpuset.7, credentials.7, feature_test_macros.7, fifo.7, hier.7, inotify.7, intro.7, mq_overview.7, path_resolution.7, pipe.7, sem_overview.7, shm_overview.7, spufs.7, symlink.7, unix.7, uri.7, sync.8: Global fix: s/file system/filesystem/
Notwithstanding 24d01c530c5a3f75217543d02bf6712395e5f90c,
"filesystem" is the form used by the great majority of man pages
outside the man-pages project and in a number of other sources,
so let's go with that.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2013-08-08 08:07:57 +00:00
|
|
|
On NFS filesystems, reading small amounts of data will update the
|
intro.1, _syscall.2, access.2, arch_prctl.2, cacheflush.2, chown.2, clock_getres.2, clone.2, create_module.2, fcntl.2, flock.2, get_kernel_syms.2, get_robust_list.2, get_thread_area.2, getcpu.2, getpriority.2, getrlimit.2, getrusage.2, ioprio_set.2, kexec_load.2, madvise.2, mbind.2, migrate_pages.2, mknod.2, mmap.2, mount.2, move_pages.2, mprotect.2, open.2, pause.2, pciconfig_read.2, perf_event_open.2, prctl.2, ptrace.2, query_module.2, read.2, reboot.2, recv.2, s390_runtime_instr.2, sched_setscheduler.2, select_tut.2, send.2, set_mempolicy.2, setfsgid.2, setfsuid.2, sigaction.2, spu_create.2, spu_run.2, stime.2, swapon.2, syslog.2, timer_create.2, timer_getoverrun.2, times.2, tkill.2, umount.2, unimplemented.2, ustat.2, vm86.2, wait.2, abs.3, aio_read.3, aio_write.3, bsd_signal.3, catgets.3, clearenv.3, cmsg.3, dbopen.3, dirfd.3, dlopen.3, exec.3, fenv.3, ferror.3, fmemopen.3, fnmatch.3, fopen.3, futimes.3, getaddrinfo.3, getifaddrs.3, getipnodebyname.3, hsearch.3, if_nameindex.3, inet_pton.3, mblen.3, mbrlen.3, mbsrtowcs.3, mbtowc.3, mcheck.3, memfrob.3, mq_notify.3, netlink.3, posix_memalign.3, printf.3, pthread_attr_setscope.3, pthread_cleanup_push.3, pthread_kill_other_threads_np.3, pthread_self.3, pthread_setcancelstate.3, pthread_setconcurrency.3, raise.3, resolver.3, rpc.3, rtime.3, rtnetlink.3, scanf.3, setbuf.3, setnetgrent.3, shm_open.3, sigpause.3, sigset.3, sigwait.3, sockatmark.3, strcasecmp.3, strcmp.3, strdup.3, strftime.3, strptime.3, strsignal.3, strverscmp.3, sysv_signal.3, termios.3, wcrtomb.3, wcsnlen.3, wcsnrtombs.3, wcsrtombs.3, wctomb.3, wprintf.3, console_codes.4, cpuid.4, msr.4, rtc.4, sk98lin.4, st.4, tty.4, charmap.5, core.5, elf.5, hosts.equiv.5, proc.5, resolv.conf.5, services.5, slabinfo.5, arp.7, bootparam.7, capabilities.7, charsets.7, cpuset.7, ddp.7, epoll.7, feature_test_macros.7, futex.7, hier.7, icmp.7, inotify.7, ip.7, ipv6.7, man-pages.7, mdoc.7, mdoc.samples.7, netdevice.7, netlink.7, numa.7, packet.7, path_resolution.7, posixoptions.7, pthreads.7, raw.7, rtld-audit.7, rtnetlink.7, sem_overview.7, sigevent.7, socket.7, spufs.7, tcp.7, udp.7, unicode.7, uri.7, utf-8.7, intro.8, ldconfig.8, sync.8: Global fix: fix placement of word "only"
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2013-03-31 08:53:00 +00:00
|
|
|
timestamp only the first time, subsequent calls may not do so.
|
2007-04-12 22:42:49 +00:00
|
|
|
This is caused
|
2004-11-03 13:51:07 +00:00
|
|
|
by client side attribute caching, because most if not all NFS clients
|
2015-05-11 09:39:38 +00:00
|
|
|
leave
|
|
|
|
|
.I st_atime
|
|
|
|
|
(last file access time)
|
|
|
|
|
updates to the server, and client side reads satisfied from the
|
|
|
|
|
client's cache will not cause
|
|
|
|
|
.I st_atime
|
|
|
|
|
updates on the server as there are no
|
|
|
|
|
server-side reads.
|
|
|
|
|
UNIX semantics can be obtained by disabling client-side attribute caching,
|
|
|
|
|
but in most situations this will substantially
|
2004-11-03 13:51:07 +00:00
|
|
|
increase server load and decrease performance.
|
2014-05-04 08:24:30 +00:00
|
|
|
.SH BUGS
|
|
|
|
|
According to POSIX.1-2008/SUSv4 Section XSI 2.9.7
|
|
|
|
|
("Thread Interactions with Regular File Operations"):
|
_syscall.2, bpf.2, cacheflush.2, capget.2, chdir.2, chmod.2, chroot.2, clock_getres.2, clock_nanosleep.2, clone.2, close.2, connect.2, copy_file_range.2, create_module.2, delete_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, execveat.2, fallocate.2, flock.2, fork.2, fsync.2, futex.2, futimesat.2, get_kernel_syms.2, get_mempolicy.2, get_robust_list.2, getcpu.2, getdents.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpriority.2, getrandom.2, getresuid.2, getrlimit.2, getrusage.2, getsid.2, getsockname.2, getsockopt.2, gettid.2, gettimeofday.2, getuid.2, getunwind.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_fat.2, ioctl_ficlonerange.2, ioctl_fideduperange.2, ioctl_tty.2, ioctl_userfaultfd.2, ioperm.2, iopl.2, ioprio_set.2, kcmp.2, kexec_load.2, keyctl.2, kill.2, link.2, listen.2, listxattr.2, llseek.2, lookup_dcookie.2, lseek.2, madvise.2, mbind.2, membarrier.2, memfd_create.2, migrate_pages.2, mincore.2, mkdir.2, mknod.2, mlock.2, mmap.2, mmap2.2, modify_ldt.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_by_handle_at.2, outb.2, perf_event_open.2, perfmonctl.2, personality.2, pivot_root.2, pkey_alloc.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, readv.2, reboot.2, recv.2, recvmmsg.2, remap_file_pages.2, rename.2, request_key.2, restart_syscall.2, rt_sigqueueinfo.2, s390_pci_mmio_write.2, s390_runtime_instr.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setattr.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, seccomp.2, select.2, select_tut.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, sendmmsg.2, set_mempolicy.2, set_thread_area.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setns.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, sgetmask.2, shmctl.2, shmget.2, shmop.2, sigaction.2, sigaltstack.2, sigpending.2, sigprocmask.2, sigreturn.2, sigsuspend.2, sigwaitinfo.2, socket.2, socketcall.2, socketpair.2, splice.2, spu_create.2, spu_run.2, stat.2, statfs.2, statx.2, subpage_prot.2, swapon.2, symlink.2, sync.2, sync_file_range.2, syscalls.2, sysctl.2, sysinfo.2, syslog.2, tee.2, time.2, timer_create.2, timer_getoverrun.2, timer_settime.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, unimplemented.2, unlink.2, unshare.2, uselib.2, userfaultfd.2, utime.2, utimensat.2, vfork.2, vmsplice.2, wait.2, wait4.2, write.2: Formatting fix: replace blank lines with .PP/.IP
Blank lines shouldn't generally appear in *roff source (other
than in code examples), since they create large vertical
spaces between text blocks.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-16 07:30:51 +00:00
|
|
|
.PP
|
2014-05-04 08:24:30 +00:00
|
|
|
.RS 4
|
|
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|
|
All of the following functions shall be atomic with respect to
|
|
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|
each other in the effects specified in POSIX.1-2008 when they
|
|
|
|
|
operate on regular files or symbolic links: ...
|
|
|
|
|
.RE
|
_syscall.2, bpf.2, cacheflush.2, capget.2, chdir.2, chmod.2, chroot.2, clock_getres.2, clock_nanosleep.2, clone.2, close.2, connect.2, copy_file_range.2, create_module.2, delete_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, execveat.2, fallocate.2, flock.2, fork.2, fsync.2, futex.2, futimesat.2, get_kernel_syms.2, get_mempolicy.2, get_robust_list.2, getcpu.2, getdents.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpriority.2, getrandom.2, getresuid.2, getrlimit.2, getrusage.2, getsid.2, getsockname.2, getsockopt.2, gettid.2, gettimeofday.2, getuid.2, getunwind.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_fat.2, ioctl_ficlonerange.2, ioctl_fideduperange.2, ioctl_tty.2, ioctl_userfaultfd.2, ioperm.2, iopl.2, ioprio_set.2, kcmp.2, kexec_load.2, keyctl.2, kill.2, link.2, listen.2, listxattr.2, llseek.2, lookup_dcookie.2, lseek.2, madvise.2, mbind.2, membarrier.2, memfd_create.2, migrate_pages.2, mincore.2, mkdir.2, mknod.2, mlock.2, mmap.2, mmap2.2, modify_ldt.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_by_handle_at.2, outb.2, perf_event_open.2, perfmonctl.2, personality.2, pivot_root.2, pkey_alloc.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, readv.2, reboot.2, recv.2, recvmmsg.2, remap_file_pages.2, rename.2, request_key.2, restart_syscall.2, rt_sigqueueinfo.2, s390_pci_mmio_write.2, s390_runtime_instr.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setattr.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, seccomp.2, select.2, select_tut.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, sendmmsg.2, set_mempolicy.2, set_thread_area.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setns.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, sgetmask.2, shmctl.2, shmget.2, shmop.2, sigaction.2, sigaltstack.2, sigpending.2, sigprocmask.2, sigreturn.2, sigsuspend.2, sigwaitinfo.2, socket.2, socketcall.2, socketpair.2, splice.2, spu_create.2, spu_run.2, stat.2, statfs.2, statx.2, subpage_prot.2, swapon.2, symlink.2, sync.2, sync_file_range.2, syscalls.2, sysctl.2, sysinfo.2, syslog.2, tee.2, time.2, timer_create.2, timer_getoverrun.2, timer_settime.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, unimplemented.2, unlink.2, unshare.2, uselib.2, userfaultfd.2, utime.2, utimensat.2, vfork.2, vmsplice.2, wait.2, wait4.2, write.2: Formatting fix: replace blank lines with .PP/.IP
Blank lines shouldn't generally appear in *roff source (other
than in code examples), since they create large vertical
spaces between text blocks.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-16 07:30:51 +00:00
|
|
|
.PP
|
2014-05-04 08:24:30 +00:00
|
|
|
Among the APIs subsequently listed are
|
|
|
|
|
.BR read ()
|
|
|
|
|
and
|
|
|
|
|
.BR readv (2).
|
|
|
|
|
And among the effects that should be atomic across threads (and processes)
|
|
|
|
|
are updates of the file offset.
|
|
|
|
|
However, on Linux before version 3.14,
|
|
|
|
|
this was not the case: if two processes that share
|
|
|
|
|
an open file description (see
|
|
|
|
|
.BR open (2))
|
|
|
|
|
perform a
|
|
|
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|
.BR read ()
|
|
|
|
|
(or
|
|
|
|
|
.BR readv (2))
|
|
|
|
|
at the same time, then the I/O operations were not atomic
|
|
|
|
|
with respect updating the file offset,
|
|
|
|
|
with the result that the reads in the two processes
|
|
|
|
|
might (incorrectly) overlap in the blocks of data that they obtained.
|
|
|
|
|
This problem was fixed in Linux 3.14.
|
|
|
|
|
.\" http://thread.gmane.org/gmane.linux.kernel/1649458
|
|
|
|
|
.\" From: Michael Kerrisk (man-pages <mtk.manpages <at> gmail.com>
|
|
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|
|
.\" Subject: Update of file offset on write() etc. is non-atomic with I/O
|
|
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|
.\" Date: 2014-02-17 15:41:37 GMT
|
|
|
|
|
.\" Newsgroups: gmane.linux.kernel, gmane.linux.file-systems
|
|
|
|
|
.\" commit 9c225f2655e36a470c4f58dbbc99244c5fc7f2d4
|
|
|
|
|
.\" Author: Linus Torvalds <torvalds@linux-foundation.org>
|
|
|
|
|
.\" Date: Mon Mar 3 09:36:58 2014 -0800
|
2014-05-08 09:04:30 +00:00
|
|
|
.\"
|
2014-05-04 08:24:30 +00:00
|
|
|
.\" vfs: atomic f_pos accesses as per POSIX
|
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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2004-11-03 13:51:07 +00:00
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.BR close (2),
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.BR fcntl (2),
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.BR ioctl (2),
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.BR lseek (2),
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2005-10-10 13:07:32 +00:00
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.BR open (2),
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2006-02-08 04:18:25 +00:00
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.BR pread (2),
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2004-11-03 13:51:07 +00:00
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.BR readdir (2),
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.BR readlink (2),
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2006-05-29 04:48:26 +00:00
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.BR readv (2),
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2004-11-03 13:51:07 +00:00
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.BR select (2),
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.BR write (2),
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2006-05-29 04:48:26 +00:00
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.BR fread (3)
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