This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the corresponding Linux
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implemented on Linux.
aio_fsync — asynchronous file synchronization
int aio_fsync(int op, struct aiocb *aiocbp);
() function shall asynchronously perform a file
synchronization operation, as specified by the op
argument, for I/O
operations associated with the file indicated by the file descriptor
member of the aiocb
structure referenced by the
argument and queued at the time of the call to
(). The function call shall return when the synchronization
request has been initiated or queued to the file or device (even when the data
cannot be synchronized immediately).
is O_DSYNC, all currently queued I/O operations shall be completed
as if by a call to fdatasync
(); that is, as defined for synchronized
I/O data integrity completion.
is O_SYNC, all currently queued I/O operations shall be completed
as if by a call to fsync
(); that is, as defined for synchronized I/O
file integrity completion. If the aio_fsync
() function fails, or if the
operation queued by aio_fsync
() fails, then outstanding I/O operations
are not guaranteed to have been completed.
() succeeds, then it is only the I/O that was queued at the
time of the call to aio_fsync
() that is guaranteed to be forced to the
relevant completion state. The completion of subsequent I/O on the file
descriptor is not guaranteed to be completed in a synchronized fashion.
argument refers to an asynchronous I/O control block. The
value may be used as an argument to aio_error
() in order to determine the error status and return status,
respectively, of the asynchronous operation while it is proceeding. When the
request is queued, the error status for the operation is [EINPROGRESS]
When all data has been successfully transferred, the error status shall be
reset to reflect the success or failure of the operation. If the operation
does not complete successfully, the error status for the operation shall be
set to indicate the error. The aio_sigevent
member determines the
asynchronous notification to occur as specified in Section 2.4.1
Signal Generation and Delivery
when all operations have achieved
synchronized I/O completion. All other members of the structure referenced by
are ignored. If the control block referenced by aiocbp
becomes an illegal address prior to asynchronous I/O completion, then the
behavior is undefined.
If the aio_fsync
() function fails or aiocbp
indicates an error
condition, data is not guaranteed to have been successfully transferred.
() function shall return the value 0 if the I/O operation is
successfully queued; otherwise, the function shall return the value −1
and set errno
to indicate the error.
() function shall fail if:
- The requested asynchronous operation was not queued due to
temporary resource limitations.
- The aio_fildes member of the aiocb structure
referenced by the aiocbp argument is not a valid file descriptor
open for writing.
- This implementation does not support synchronized I/O for
- The aio_fildes member of the aiocb structure
refers to a file on which an fsync() operation is not
- A value of op other than O_DSYNC or O_SYNC was
specified, or O_DSYNC was specified and the implementation does not
provide runtime support for the Synchronized Input and Output option, or
O_SYNC was specified and the implementation does not provide runtime
support for the File Synchronization option.
In the event that any of the queued I/O operations fail, aio_fsync
shall return the error condition defined for read
() and write
The error is returned in the error status for the asynchronous operation,
which can be retrieved using aio_error
The following sections are informative.
The Base Definitions volume of POSIX.1‐2008, <aio.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 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 .
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