AIO_FSYNC(3P) POSIX Programmer s Manual AIO_FSYNC(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.
NAME aio_fsync - asynchronous file synchronization (REALTIME)
SYNOPSIS #include <aio.h>
int aio_fsync(int op, struct aiocb *aiocbp);
DESCRIPTION The aio_fsync() function shall asynchronously force all I/O operations associated with the file indicated by the file descriptor aio_fildes member of the aiocb structure referenced by the aiocbp argument and queued at the time of the call to aio_fsync() to the synchronized I/O completion state. The function call shall return when the synchroniza- tion request has been initiated or queued to the file or device (even when the data cannot be synchronized immediately).
If op is O_DSYNC, all currently queued I/O operations shall be com- pleted as if by a call to fdatasync(); that is, as defined for synchro- nized I/O data integrity completion. If op 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, as for fsync() and fdatasync(), outstanding I/O operations are not guaranteed to have been completed.
If aio_fsync() 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.
The aiocbp argument refers to an asynchronous I/O control block. The aiocbp value may be used as an argument to aio_error() and aio_return() 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 oper- ation does not complete successfully, the error status for the opera- tion shall be set to indicate the error. The aio_sigevent member determines the asynchronous notification to occur as specified in Sig- nal Generation and Delivery when all operations have achieved synchro- nized I/O completion. All other members of the structure referenced by aiocbp 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 condi- tion, data is not guaranteed to have been successfully transferred.
RETURN VALUE The aio_fsync() function shall return the value 0 to the calling pro- cess if the I/O operation is successfully queued; otherwise, the func- tion shall return the value -1 and set errno to indicate the error.
ERRORS The aio_fsync() function shall fail if:
EAGAIN The requested asynchronous operation was not queued due to tem- porary resource limitations.
EBADF The aio_fildes member of the aiocb structure referenced by the aiocbp argument is not a valid file descriptor open for writing.
EINVAL This implementation does not support synchronized I/O for this file.
EINVAL A value of op other than O_DSYNC or O_SYNC was specified.
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 fsync() operation, which can be retrieved using aio_error().
The following sections are informative.
APPLICATION USAGE The aio_fsync() function is part of the Asynchronous Input and Output option and need not be available on all implementations.
FUTURE DIRECTIONS None.
SEE ALSO fcntl(), fdatasync(), fsync(), open(), read(), write(), the Base Defi- nitions volume of IEEE Std 1003.1-2001, <aio.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 AIO_FSYNC(3P)