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



NAME
       sync - commit buffer cache to disk

SYNOPSIS
       #include <unistd.h>

       void sync(void);

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

       sync(): _BSD_SOURCE || _XOPEN_SOURCE >= 500

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

ERRORS
       This function is always successful.

CONFORMING TO
       SVr4, 4.3BSD, POSIX.1-2001.

NOTES
       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
       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), update(8)

COLOPHON
       This page is part of release 3.25 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                                                      2007-07-26                                                    SYNC(2)