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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 3.24 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/.