97 lines
3 KiB
Groff
97 lines
3 KiB
Groff
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.\" $NetBSD: fdatasync.2,v 1.16 2008/04/30 13:10:51 martin Exp $
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.\"
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.\" Copyright (c) 1998 The NetBSD Foundation, Inc.
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.\" All rights reserved.
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.\"
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.\" This code is derived from software contributed to The NetBSD Foundation
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.\" by Klaus Klein.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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.\" POSSIBILITY OF SUCH DAMAGE.
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.\"
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.Dd October 25, 2003
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.Dt FDATASYNC 2
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.Os
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.Sh NAME
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.Nm fdatasync
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.Nd synchronize the data of a file
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In unistd.h
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.Ft int
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.Fn fdatasync "int fd"
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.Sh DESCRIPTION
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The
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.Fn fdatasync
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function forces all modified data associated with the file descriptor
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.Fa fd
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to be flushed to stable storage.
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.Pp
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The functionality is as described for
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.Xr fsync 2 ,
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with the exception that file status information need not be synchronized,
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which may result in a performance gain, compared to
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.Xr fsync 2 .
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This behaviour is commonly known as
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.Bf -symbolic
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synchronized I/O data integrity completion.
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.Ef
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.Sh RETURN VALUES
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A value of 0 is returned on success.
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Otherwise, a value \-1 is returned and
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.Va errno
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is set to indicate the error.
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.Sh ERRORS
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The
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.Fn fdatasync
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function will fail if:
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.Bl -tag -width Er
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.It Bq Er EBADF
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The
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.Fa fd
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argument is not a valid file descriptor open for writing.
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.It Bq Er EINVAL
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This implementation does not support synchronized I/O for this file.
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.It Bq Er ENOSYS
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The
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.Fn fdatasync
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function is not supported by this implementation.
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.El
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.Pp
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In the event that any of the I/O operations to be performed fail,
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.Fn fdatasync
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returns the error conditions defined for
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.Xr read 2
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and
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.Xr write 2 ,
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and outstanding I/O operations are not guaranteed to have been completed.
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.Sh SEE ALSO
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.Xr fsync 2 ,
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.Xr open 2 ,
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.Xr read 2 ,
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.Xr write 2
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.Sh STANDARDS
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The
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.Fn fdatasync
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function conforms to
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.St -p1003.1b-93 .
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