FDATASYNC(3P) POSIX Programmer's Manual FDATASYNC(3P)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.
fdatasync — synchronize the data of a file (REALTIME)
int fdatasync(int fildes);
The fdatasync() function shall force all currently queued I/O opera‐
tions 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 opera‐
tions shall be completed as defined for synchronized I/O data integrity
If successful, the fdatasync() function shall return the value 0; oth‐
erwise, the function shall return the value −1 and set errno to indi‐
cate the error. If the fdatasync() function fails, outstanding I/O
operations are not guaranteed to have been completed.
The fdatasync() function shall fail if:
EBADF The fildes argument is not a valid file descriptor open for
EINVAL This implementation does not support synchronized I/O for this
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.
SEE ALSOaio_fsync(), fcntl(), fsync(), open(), read(), write()
The Base Definitions volume of POSIX.1‐2008, <unistd.h>
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 Electri‐
cal 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 .
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IEEE/The Open Group 2013 FDATASYNC(3P)