NAME | SYNOPSIS | DESCRIPTION | ERRORS | CONFORMING TO | NOTES | BUGS | SEE ALSO | COLOPHON

The Linux Programming Interface

SYNC(2)                       Linux Programmer's Manual                       SYNC(2)

NAME         top

       sync - commit buffer cache to disk

SYNOPSIS         top

       #include <unistd.h>

       void sync(void);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       sync():
           _BSD_SOURCE || _XOPEN_SOURCE >= 500 ||
           _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED

DESCRIPTION         top

       sync() first commits inodes to buffers, and then buffers to disk.

ERRORS         top

       This function is always successful.

CONFORMING TO         top

       SVr4, 4.3BSD, POSIX.1-2001.

NOTES         top

       Since glibc 2.2.2 the Linux prototype 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         top

       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         top

       bdflush(2), fdatasync(2), fsync(2), sync(8), update(8)

COLOPHON         top

       This page is part of release 3.32 of the Linux man-pages project.  A
       description of the project, and information about reporting bugs, can be found
       at http://www.kernel.org/doc/man-pages/.

Linux                                 2010-09-20                              SYNC(2)

HTML rendering created 2010-12-03 by Michael Kerrisk, author of The Linux Programming Interface