PROLOG

       This  manual  page  is part of the POSIX Programmer's Manual.  The Linux implementation of this interface
       may differ (consult the corresponding Linux manual page for details of Linux behavior), or the  interface
       may not be implemented on Linux.

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 POSIX.1‐2008, <unistd.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition,
       Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open  Group  Base
       Specifications  Issue 7, Copyright (C) 2013 by the Institute of Electrical and Electronics Engineers, Inc
       and The Open Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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.unix.org/online.html .

       Any  typographical  or formatting errors that appear in this page are most likely to have been introduced
       during  the  conversion  of  the  source  files  to  man  page  format.  To  report  such   errors,   see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .