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Diffstat (limited to 'man/man2/sync.2')
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diff --git a/man/man2/sync.2 b/man/man2/sync.2 new file mode 100644 index 000000000..1c0c7d7b4 --- /dev/null +++ b/man/man2/sync.2 @@ -0,0 +1,148 @@ +.\" Copyright (c) 1992 Drew Eckhardt (drew@cs.colorado.edu), March 28, 1992 +.\" and Copyright (c) 2011 Michael Kerrisk <mtk.manpages@gmail.com> +.\" +.\" SPDX-License-Identifier: Linux-man-pages-copyleft +.\" +.\" Modified by Michael Haardt <michael@moria.de> +.\" Modified Sat Jul 24 12:02:47 1993 by Rik Faith <faith@cs.unc.edu> +.\" Modified 15 Apr 1995 by Michael Chastain <mec@shell.portal.com>: +.\" Added reference to `bdflush(2)'. +.\" Modified 960414 by Andries Brouwer <aeb@cwi.nl>: +.\" Added the fact that since 1.3.20 sync actually waits. +.\" Modified Tue Oct 22 22:27:07 1996 by Eric S. Raymond <esr@thyrsus.com> +.\" Modified 2001-10-10 by aeb, following Michael Kerrisk. +.\" 2011-09-07, mtk, Added syncfs() documentation, +.\" +.TH sync 2 (date) "Linux man-pages (unreleased)" +.SH NAME +sync, syncfs \- commit filesystem caches to disk +.SH LIBRARY +Standard C library +.RI ( libc ", " \-lc ) +.SH SYNOPSIS +.nf +.B #include <unistd.h> +.P +.B void sync(void); +.P +.BI "int syncfs(int " fd ); +.fi +.P +.RS -4 +Feature Test Macro Requirements for glibc (see +.BR feature_test_macros (7)): +.RE +.P +.BR sync (): +.nf + _XOPEN_SOURCE >= 500 +.\" || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED + || /* Since glibc 2.19: */ _DEFAULT_SOURCE + || /* glibc <= 2.19: */ _BSD_SOURCE +.fi +.P +.BR syncfs (): +.nf + _GNU_SOURCE +.fi +.SH DESCRIPTION +.BR sync () +causes all pending modifications to filesystem metadata and cached file +data to be written to the underlying filesystems. +.P +.BR syncfs () +is like +.BR sync (), +but synchronizes just the filesystem containing file +referred to by the open file descriptor +.IR fd . +.SH RETURN VALUE +.BR syncfs () +returns 0 on success; +on error, it returns \-1 and sets +.I errno +to indicate the error. +.SH ERRORS +.BR sync () +is always successful. +.P +.BR syncfs () +can fail for at least the following reasons: +.TP +.B EBADF +.I fd +is not a valid file descriptor. +.TP +.B EIO +An error occurred during synchronization. +This error may relate to data written to any file on the filesystem, or on +metadata related to the filesystem itself. +.TP +.B ENOSPC +Disk space was exhausted while synchronizing. +.TP +.B ENOSPC +.TQ +.B EDQUOT +Data was written to a file on NFS or another filesystem which does not +allocate space at the time of a +.BR write (2) +system call, and some previous write failed due to insufficient +storage space. +.SH VERSIONS +According to the standard specification (e.g., POSIX.1-2001), +.BR sync () +schedules the writes, but may return before the actual +writing is done. +However Linux waits for I/O completions, +and thus +.BR sync () +or +.BR syncfs () +provide the same guarantees as +.BR fsync () +called on every file in +the system or filesystem respectively. +.SH STANDARDS +.TP +.BR sync () +POSIX.1-2008. +.TP +.BR syncfs () +Linux. +.SH HISTORY +.TP +.BR sync () +POSIX.1-2001, SVr4, 4.3BSD. +.TP +.BR syncfs () +Linux 2.6.39, +glibc 2.14. +.P +Since glibc 2.2.2, the Linux prototype for +.BR sync () +is as listed above, +following the various standards. +In glibc 2.2.1 and earlier, +it was "int sync(void)", and +.BR sync () +always returned 0. +.P +In mainline kernel versions prior to Linux 5.8, +.BR syncfs () +will fail only when passed a bad file descriptor +.RB ( EBADF ). +Since Linux 5.8, +.\" commit 735e4ae5ba28c886d249ad04d3c8cc097dad6336 +.BR syncfs () +will also report an error if one or more inodes failed +to be written back since the last +.BR syncfs () +call. +.SH BUGS +Before Linux 1.3.20, Linux did not wait for I/O to complete +before returning. +.SH SEE ALSO +.BR sync (1), +.BR fdatasync (2), +.BR fsync (2) |