fdatasync - Writes data changes in a file to permanent
int fdatasync (
int fildes );
Specifies a valid open file descriptor.
The fdatasync function causes system buffers containing a
file's modified data to be written to permanent storage.
The fdatasync function does not return until the operation
has been completed. The fdatasync function provides data
integrity, ensuring that data in permanent storage is
identical to data in the buffer. However, use of fdatasync
does not guarantee that file control information such as
owner and modification time has been updated to permanent
storage (see the fsync function).
The file identified by the fildes parameter must be open
for writing when the fdatasync function is issued or the
call will fail.
Upon successful completion, the fdatasync function returns
a value of 0 (zero). If the fdatasync function fails, a
value of -1 is returned and errno is set to indicate the
error. If fdatasync fails, outstanding I/O operations are
not guaranteed to have been completed.
If the fdatasync function fails, errno may be set to one
of the following values: The fildes parameter is not a
valid file descriptor. The fildes parameter does not
refer to a file on which this operation is possible.
If any queued I/O operations fail, the fdatasync function
returns error conditions defined for the read and write
Functions: fcntl(2), fsync(2), open(2), read(2), sync(2),
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