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32 .Nd asynchronous file synchronization (REALTIME)
38 .Fn aio_fsync "int op" "struct aiocb *iocb"
42 system call allows the calling process to move all modified data
43 associated with the descriptor
45 to a permanent storage device.
46 The call returns immediately after the synchronization request has been
47 enqueued to the descriptor; the synchronization may or may not have
48 completed at the time the call returns.
52 argument can only be set to
54 to cause all currently queued I/O operations to be completed
58 If _POSIX_PRIORITIZED_IO is defined, and the descriptor supports it,
59 then the enqueued operation is submitted at a priority equal to that
60 of the calling process minus
61 .Fa iocb->aio_reqprio .
65 pointer may be subsequently used as an argument to
69 in order to determine return or error status for the enqueued operation
70 while it is in progress.
72 If the request could not be enqueued (generally due to invalid arguments),
73 the call returns without having enqueued the request.
76 .Fa iocb->aio_sigevent
77 structure can be used to request notification of the operation's
78 completion as described in
81 The Asynchronous I/O Control Block structure pointed to by
83 must remain valid until the
84 operation has completed.
86 The asynchronous I/O control buffer
88 should be zeroed before the
90 call to avoid passing bogus context information to the kernel.
92 Modification of the Asynchronous I/O Control Block structure is not allowed
93 while the request is queued.
99 system call will fail if:
102 The request was not queued because of system resource limitations.
104 The asynchronous notification method in
105 .Fa iocb->aio_sigevent.sigev_notify
106 is invalid or not supported.
108 Asynchronous file synchronization operations on the file descriptor
110 are unsafe and unsafe asynchronous I/O operations are disabled.
114 argument is not set to
118 The following conditions may be synchronously detected when the
120 system call is made, or asynchronously, at any time thereafter.
121 If they are detected at call time,
125 appropriately; otherwise the
127 system call must be called, and will return -1, and
129 must be called to determine the actual value that would have been
137 is not a valid descriptor.
139 This implementation does not support synchronized I/O for this file.
142 If the request is successfully enqueued, but subsequently cancelled
143 or an error occurs, the value returned by the
145 system call is per the
149 system calls, and the value returned by the
151 system call is one of the error returns from the
162 .Xr aio_waitcomplete 2 ,
171 system call is expected to conform to the
177 system call first appeared in