x SuSE Linux 13.1-RELEASE x
x SuSE Linux 13.1-RELEASEx
SYNC(2) Linux Programmer's Manual SYNC(2)
NAME
sync, syncfs - commit buffer cache to disk
SYNOPSIS
#include <unistd.h>
void sync(void);
int syncfs(int fd);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
sync():
_BSD_SOURCE || _XOPEN_SOURCE >= 500 ||
_XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED
syncfs():
_GNU_SOURCE
DESCRIPTION
sync() causes all buffered modifications to file metadata and data to
be written to the underlying filesystems.
syncfs() is like sync(), but synchronizes just the filesystem contain-
ing 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(): SVr4, 4.3BSD, POSIX.1-2001.
syncfs() is Linux-specific.
NOTES
Since glibc 2.2.2 the Linux prototype for sync() is as listed above,
following the various standards. In libc4, libc5, and glibc up to
2.2.1 it was "int sync(void)", and sync() always returned 0.
BUGS
According to the standard specification (e.g., POSIX.1-2001), sync()
schedules the writes, but may return before the actual writing is done.
However, since version 1.3.20 Linux does actually wait. (This still
does not guarantee data integrity: modern disks have large caches.)
SEE ALSO
bdflush(2), fdatasync(2), fsync(2), sync(8)
COLOPHON
This page is part of release 3.69 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
http://www.kernel.org/doc/man-pages/.
Linux 2014-04-06 SYNC(2)
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