NAME

       fdatasync - synchronize the data of a file (REALTIME)

SYNOPSIS

       #include <unistd.h>

       int fdatasync(int fildes);

DESCRIPTION

       The  fdatasync()  function  shall  force  all  currently  queued  I/O operations associated with the file
       indicated by file descriptor fildes to the synchronized I/O completion state.

       The functionality shall be equivalent to fsync() with the symbol _POSIX_SYNCHRONIZED_IO defined, with the
       exception that all I/O operations shall be completed as  defined  for  synchronized  I/O  data  integrity
       completion.

RETURN VALUE

       If  successful,  the  fdatasync() function shall return the value 0; otherwise, the function shall return
       the value -1 and set errno to indicate the error. If the  fdatasync()  function  fails,  outstanding  I/O
       operations are not guaranteed to have been completed.

ERRORS

       The fdatasync() function shall fail if:

       EBADF  The fildes argument is not a valid file descriptor open for writing.

       EINVAL This implementation does not support synchronized I/O for this file.

       In  the  event  that any of the queued I/O operations fail, fdatasync() shall return the error conditions
       defined for read() and write().

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       aio_fsync() , fcntl() ,  fsync()  ,  open()  ,  read()  ,  write()  ,  the  Base  Definitions  volume  of
       IEEE Std 1003.1-2001, <unistd.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition,
       Standard  for  Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers,
       Inc and The Open Group. In the event of any discrepancy between this version and the  original  IEEE  and
       The  Open  Group  Standard,  the  original  IEEE and The Open Group Standard is the referee document. The
       original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

IEEE/The Open Group                                   2003                                          FDATASYNC(P)