SYNC
Section: User Commands (1)Updated: January 2018
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NAME
sync - Synchronize cached writes to persistent storageSYNOPSIS
sync [,OPTION/] [,FILE/]...DESCRIPTION
Synchronize cached writes to persistent storage
If one or more files are specified, sync only them, or their containing file systems.
- -d, --data
- sync only file data, no unneeded metadata
- -f, --file-system
- sync the file systems that contain the files
- --help
- display this help and exit
- --version
- output version information and exit
BUGS
Persistence guarantees vary per system. See the system calls below for more details.AUTHOR
Written by Jim Meyering and Giuseppe Scrivano.REPORTING BUGS
GNU coreutils online help: <http://www.gnu.org/software/coreutils/>Report sync translation bugs to <http://translationproject.org/team/>
COPYRIGHT
Copyright © 2017 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.
SEE ALSO
fdatasync(2), fsync(2), sync(2), syncfs(2)
Full documentation at: <http://www.gnu.org/software/coreutils/sync>
or available locally via: info '(coreutils) sync invocation'
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SYNC
Section: Linux Programmer's Manual (2)Updated: 2017-09-15
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NAME
sync, syncfs - commit filesystem caches to diskSYNOPSIS
#include <unistd.h>void sync(void);
int syncfs(int fd);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
sync():
-
_XOPEN_SOURCE >= 500
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc versions <= 2.19: */ _BSD_SOURCE
syncfs():
- _GNU_SOURCE
DESCRIPTION
sync() causes all pending modifications to filesystem metadata and cached file data to be written to the underlying filesystems.syncfs() is like sync(), but synchronizes just the filesystem containing file referred to by the open file descriptor fd.
RETURN VALUE
syncfs() returns 0 on success; on error, it returns -1 and sets errno to indicate the error.ERRORS
sync() is always successful.syncfs() can fail for at least the following reason:
- EBADF
- fd is not a valid file descriptor.
VERSIONS
syncfs() first appeared in Linux 2.6.39; library support was added to glibc in version 2.14.CONFORMING TO
sync(): POSIX.1-2001, POSIX.1-2008, SVr4, 4.3BSD.NOTES
Since glibc 2.2.2, the Linux prototype for sync() is as listed above, following the various standards. In glibc 2.2.1 and earlier, it was "int sync(void)", and sync() always returned 0.According to the standard specification (e.g., POSIX.1-2001), sync() schedules the writes, but may return before the actual writing is done. However Linux waits for I/O completions, and thus sync() or syncfs() provide the same guarantees as fsync called on every file in the system or filesystem respectively.
BUGS
Before version 1.3.20 Linux did not wait for I/O to complete before returning.SEE ALSO
sync(1), fdatasync(2), fsync(2)COLOPHON
This page is part of release 4.15 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.
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Time: 04:45:34 GMT, September 16, 2022
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