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30 .Nd asynchronous file synchronization (REALTIME)
36 .Fn aio_fsync "int op" "struct aiocb *iocb"
40 system call allows the calling process to move all modified data
41 associated with the descriptor
43 to a permanent storage device.
44 The call returns immediately after the synchronization request has been
45 enqueued to the descriptor; the synchronization may or may not have
46 completed at the time the call returns.
50 argument can be set to
52 to cause all currently queued I/O operations to be completed
60 If _POSIX_PRIORITIZED_IO is defined, and the descriptor supports it,
61 then the enqueued operation is submitted at a priority equal to that
62 of the calling process minus
63 .Fa iocb->aio_reqprio .
67 pointer may be subsequently used as an argument to
71 in order to determine return or error status for the enqueued operation
72 while it is in progress.
74 If the request could not be enqueued (generally due to invalid arguments),
75 the call returns without having enqueued the request.
78 .Fa iocb->aio_sigevent
79 structure can be used to request notification of the operation's
80 completion as described in
83 The Asynchronous I/O Control Block structure pointed to by
85 must remain valid until the
86 operation has completed.
88 The asynchronous I/O control buffer
90 should be zeroed before the
92 call to avoid passing bogus context information to the kernel.
94 Modification of the Asynchronous I/O Control Block structure is not allowed
95 while the request is queued.
101 system call will fail if:
104 The request was not queued because of system resource limitations.
106 The asynchronous notification method in
107 .Fa iocb->aio_sigevent.sigev_notify
108 is invalid or not supported.
110 Asynchronous file synchronization operations on the file descriptor
112 are unsafe and unsafe asynchronous I/O operations are disabled.
116 argument is not set to
122 The following conditions may be synchronously detected when the
124 system call is made, or asynchronously, at any time thereafter.
125 If they are detected at call time,
129 appropriately; otherwise the
131 system call must be called, and will return -1, and
133 must be called to determine the actual value that would have been
141 is not a valid descriptor.
143 This implementation does not support synchronized I/O for this file.
146 If the request is successfully enqueued, but subsequently cancelled
147 or an error occurs, the value returned by the
149 system call is per the
153 system calls, and the value returned by the
155 system call is one of the error returns from the
166 .Xr aio_waitcomplete 2 ,
175 system call is expected to conform to the
181 system call first appeared in