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AIO_FSYNC(2) System Calls Manual AIO_FSYNC(2) NAME aio_fsync -- asynchronous file synchronization (REALTIME) LIBRARY Standard C Library (libc, -lc) SYNOPSIS #include <aio.h> int aio_fsync(int op, struct aiocb *iocb); DESCRIPTION The aio_fsync() system call allows the calling process to move all mod- ified data associated with the descriptor iocb-_aio_fildes to a perma- nent storage device. The call returns immediately after the synchro- nization request has been enqueued to the descriptor; the synchroniza- tion may or may not have completed at the time the call returns. The op argument can be set to O_SYNC to cause all currently queued I/O operations to be completed as if by a call to fsync(2), or O_DSYNC for the behavior of fdatasync(2). If _POSIX_PRIORITIZED_IO is defined, and the descriptor supports it, then the enqueued operation is submitted at a priority equal to that of the calling process minus iocb-_aio_reqprio. The iocb pointer may be subsequently used as an argument to aio_return() and aio_error() in order to determine return or error sta- tus for the enqueued operation while it is in progress. If the request could not be enqueued (generally due to invalid argu- ments), the call returns without having enqueued the request. The iocb-_aio_sigevent structure can be used to request notification of the operation's completion as described in aio(4). RESTRICTIONS The Asynchronous I/O Control Block structure pointed to by iocb must remain valid until the operation has completed. The asynchronous I/O control buffer iocb should be zeroed before the aio_fsync() call to avoid passing bogus context information to the ker- nel. Modification of the Asynchronous I/O Control Block structure is not al- lowed while the request is queued. RETURN VALUES The aio_fsync() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indi- cate the error. ERRORS The aio_fsync() system call will fail if: [EAGAIN] The request was not queued because of system re- source limitations. [EINVAL] The asynchronous notification method in iocb-_aio_sigevent.sigev_notify is invalid or not supported. [EOPNOTSUPP] Asynchronous file synchronization operations on the file descriptor iocb-_aio_fildes are unsafe and un- safe asynchronous I/O operations are disabled. [EINVAL] A value of the op argument is not set to O_SYNC or O_DSYNC. The following conditions may be synchronously detected when the aio_fsync() system call is made, or asynchronously, at any time there- after. If they are detected at call time, aio_fsync() returns -1 and sets errno appropriately; otherwise the aio_return() system call must be called, and will return -1, and aio_error() must be called to deter- mine the actual value that would have been returned in errno. [EBADF] The iocb-_aio_fildes argument is not a valid de- scriptor. [EINVAL] This implementation does not support synchronized I/O for this file. If the request is successfully enqueued, but subsequently cancelled or an error occurs, the value returned by the aio_return() system call is per the read(2) and write(2) system calls, and the value returned by the aio_error() system call is one of the error returns from the read(2) or write(2) system calls. SEE ALSO aio_cancel(2), aio_error(2), aio_read(2), aio_return(2), aio_suspend(2), aio_waitcomplete(2), aio_write(2), fsync(2), sigevent(3), siginfo(3), aio(4) STANDARDS The aio_fsync() system call is expected to conform to the IEEE Std 1003.1 ("POSIX.1") standard. HISTORY The aio_fsync() system call first appeared in FreeBSD 7.0. The O_DSYNC option appeared in FreeBSD 13.0. FreeBSD 13.2 January 6, 2021 AIO_FSYNC(2)
NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RESTRICTIONS | RETURN VALUES | ERRORS | SEE ALSO | STANDARDS | HISTORY
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