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.
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
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.
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.
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
IEEE/The Open Group 2013 FDATASYNC(3P)