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34 .\" @(#)fsync.2 8.1 (Berkeley) 6/4/93
43 .Nd "synchronise changes to a file"
49 .Fn fdatasync "int fd"
56 causes all modified data and attributes of the file referenced by
59 to be moved to a permanent storage device.
60 This normally results in all in-core modified copies
61 of buffers for the associated file to be written to a disk.
65 system call causes all modified data of
67 to be moved to a permanent storage device.
70 the system call does not guarantee that file attributes or
71 metadata necessary to access the file are committed to the permanent storage.
76 should be used by programs that require a file to be
77 in a known state, for example, in building a simple transaction
79 If the file metadata has already been committed, using
81 can be more efficient than
88 calls are cancellation points.
102 is not a valid descriptor.
107 refers to a socket, not to a file.
109 An I/O error occurred while reading from or writing to the file system.
119 system call appeared in
123 system call appeared in
128 system call currently does not guarantee that enqueued
130 requests for the file referenced by
132 are completed before the syscall returns.